Upper layer-forming composition and photoresist patterning method

ABSTRACT

An upper layer-forming composition includes a resin, and a solvent. The resin is dissolvable in a developer for a photoresist film which is to be covered by the upper layer-forming composition to form a pattern by exposure to radiation. The solvent dissolves the resin in the solvent. The solvent includes a compound shown by a formula (1). Each of R 1  and R 2  independently represents a hydrocarbon group having 1 to 8 carbon atoms or a halogenated hydrocarbon group. 
       R 1 —O—R 2   (1)

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of the U.S. patentapplication Ser. No. 12/091,712, filed on Apr. 25, 2008, which in turnis a national stage application of International Application No.PCT/JP2006/321247, filed on Oct. 25, 2006, which claims priority under35 U.S.C. §119 to Japanese Patent Application No. 2005-312775, filed onOct. 27, 2005, and to Japanese Patent Application No. 2006-85223, filedon Mar. 27, 2006. The contents of these applications are incorporatedherein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an upper layer-forming composition anda photoresist patterning method.

2. Discussion of the Background

A stepper-type or step-and-scan-type projection aligner is used in themanufacture of semiconductor devices and the like to transfer a reticlepattern as a photo mask to each shot region on a wafer coated with aphotoresist through a projection optical system.

The resolution of a projection optical system provided in the projectionaligner increases as the exposure wavelength used becomes shorter andthe numerical aperture of the projection optical system becomes greater.Therefore, the exposure wavelength which is a wavelength of radiationused in the projection aligner has been reduced in accordance withscaling down of integrated circuits year by year, and the numericalaperture of the projection optical system has been increased.

Depth of focus is as important as resolution. Resolution R and depth offocus δ are respectively shown by the following formulas,

R=k1·λ/NA  (i)

δ=k2·λ/NA²  (ii)

wherein λ is the exposure wavelength, NA is the numerical aperture ofthe projection optical system, and k1 and k2 are process coefficients.When obtaining the same resolution R, a larger depth of focus δ isobtained by using radiation with a shorter wavelength.

A photoresist film is formed on the surface of an exposure target wafer,and the pattern is transferred to the photoresist film. In a commonprojection aligner, the space in which the wafer is placed is filledwith air or nitrogen. When the space between the wafer and the lens ofthe projection aligner is filled with a medium having a refractive indexof n, the resolution R and the depth of focus δ are shown by thefollowing formulas.

R=k1·(λ/n)/NA  (iii)

δ=k2·nλ/NA²  (iv)

For example, when water is used as the above medium in an ArF process,the resolution R is 69.4% (R=k1·(λ/1.44)/NA) and the depth of focus is144% (δ=k2·1.44λ/NA²) in the case in which the photoresist is exposedthrough air or nitrogen, when the refractive index of light with awavelength of 193 nm is n=1.44.

Such a projection exposure method to transfer detailed patterns byreducing the wavelength of emitted light is called a liquid immersionlithographic method and is regarded as an essential technique forminiaturizing lithography, particularly lithography of the order ofseveral tens of nanometers. And the projection aligner for the method isalso known (see Japanese Unexamined Patent Application PublicationJP-A-11-176727).

In the liquid immersion lithographic method using water as a medium ofimmersion, a photoresist film formed on a wafer and the lens of aprojection aligner are respectively brought into contact with water. Thewater may permeate the photoresist film and reduce the photoresistresolution. In addition, the components forming the photoresist may beeluted into the water and may pollute the surface of the lens of theprojection aligner.

A method of forming an upper layer film on a photoresist film may beused in order to block contact between the photoresist film and themedium such as water. Such an upper layer film must possess sufficienttransparency to radiation with a wavelength used in liquid immersionlithography, must form a protective film on a photoresist film whilecausing almost no intermixing with the photoresist film, must be stablymaintained without being dissolved in the medium such as water duringliquid immersion lithography, and must be easily dissolved in adeveloper such as an alkaline solution.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, an upper layer-formingcomposition includes a resin, and a solvent. The resin is dissolvable ina developer for a photoresist film which is to be covered by the upperlayer-forming composition to form a pattern by exposure to radiation.The solvent dissolves the resin in the solvent. The solvent includes acompound shown by a formula (1).

R¹—O—R²  (1)

Each of R¹ and R² independently represents a hydrocarbon group having 1to 8 carbon atoms or a halogenated hydrocarbon.

According to another aspect of the present invention, a photoresistpatterning method includes applying a photoresist composition to asubstrate to form a photoresist film. The upper layer-formingcomposition is applied on the photoresist film to form an upper layerfilm. The photoresist film and the upper layer film are irradiated withradiation using a liquid as a medium through a mask having a specificpattern to form a resist pattern. The resist pattern is developed.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings.

FIG. 1 is a cross-sectional view of a line-and space pattern.

DESCRIPTION OF THE EMBODIMENTS

The embodiment of the present invention provides an upper layer-formingcomposition covering a photoresist film for forming a pattern byexposure to radiation, which includes a resin dissolvable in a developerfor the photoresist film and a solvent with a viscosity of less than5.2×10⁻³ Pa·s at 20° C. in which the resin is dissolved. The solventdoes not cause intermixing of the photoresist film and the upperlayer-forming composition.

The term “does not cause intermixing” indicates the case in which theresist coating film and the upper layer film for use in immersionlithography are judged to cause no intermixing in the later-describedevaluation of intermixing.

The solvent used for the upper layer-forming composition of theembodiment of the present invention includes a compound shown by thefollowing formula (1).

R¹—O—R²  (1)

In the formula (1), R¹ and R² individually represent a hydrocarbon grouphaving 1 to 8 carbon atoms or a halogenated hydrocarbon group.

A solvent containing the compound shown by the formula (1) is a mixturewith a monohydric alcohol solvent having 1 to 10 carbon atoms.

The upper layer-forming composition of the embodiment of the presentinvention is composed of a resin having at least one recurring unitselected from the group consisting of recurring units having a groupshown by the following formula (2), (3), or (4), a carboxyl group, and asulfo group, and has a weight average molecular weight measured by gelpermeation chromatography of 2,000 to 100,000.

In the formula (2), R³ and R⁴ individually represent a hydrogen atom, analkyl group having 1 to 4 carbon atoms, or a fluoroalkyl group having 1to 4 carbon atoms. In the formula (3), R⁵ represents a fluoroalkyl grouphaving 1 to 20 carbon atoms. In the formula (4), R⁶ represents anorganic group having a polar group.

The upper layer-forming composition of the embodiment of the presentinvention further includes at least one component selected from a groupconsisting of an acid component and an acid-generator component whichgenerates an acid by being exposed to radiation.

The photoresist patterning method of the embodiment of the presentinvention includes a step of forming a photoresist film by applying aphotoresist composition to a substrate, a step of forming an upper layerfilm on the photoresist film using the upper layer-forming compositionof the embodiment of the present invention, and a step of forming aresist pattern by irradiating the photoresist film and the upper layerfilm with radiation using a liquid as a medium through a mask having aspecific pattern, and developing the photoresist pattern.

Since the solvent used for the upper layer-forming composition of theembodiment of the present invention has a viscosity of less than5.2×10⁻³ Pa·s at 20° C., the amount of composition to be appliedhomogeneously on a silicon wafer can be reduced. In addition, since thecomposition contains the solvent comprising an ether of the formula (1)or a hydrocarbon compound having 7 to 11 carbon atoms, the compositioncan not only protect the photoresist film used in a liquid immersionlithographic method for miniaturizing lithography, but can also form anupper layer film for protecting a lens used in the projection aligner bysuppressing elusion of photoresist components. The composition thusexhibits performance equivalent to or better than the upper layer filmcomposition for use in immersion lithography in which a monohydricalcohol is used as a major component.

The embodiments will now be described with reference to the accompanyingdrawings, wherein like reference numerals designate corresponding oridentical elements throughout the various drawings.

When water is used as an immersion medium, the upper layer film madefrom the upper layer-forming composition inhibits the photoresist filmfrom coming into direct contact with water during the liquid immersionlithography, thereby preventing the photoresist film from reducing thelithographic performance due to penetration of water and preventing thelens of the projection aligner from being polluted with componentseluted from the photoresist film.

As the solvent for dissolving the resin component of the upperlayer-forming composition, a solvent exhibiting an almost no adverseeffect on the lithographic performance by intermixing and the like withthe photoresist film when applied to the photoresist film can be used.

The viscosity of the solvent used in the embodiment of the presentinvention is preferably less than 5.2×10⁻³ Pa·s at 20° C. If theviscosity of the solvent is 5.2×10⁻³ Pa·s or more at 20° C., the amountof application must be increased in order to ensure in-plane uniformity.In the embodiment of the present invention, the viscosity of the solventindicates the viscosity of the solvent as a whole.

In order to reduce the viscosity to less than 5.2×10⁻³ Pa·s, the solventpreferably contains a solvent containing the ether of the formula (1).

In the formula (1), R¹ and R² individually represent a hydrocarbon grouphaving 1 to 8 carbon atoms and a halogenated hydrocarbon group.

As examples of the solvent containing ethers shown by the formula (1),

diethyl ether, dipropyl ether, diisopropyl ether, butyl methyl ether,butyl ethyl ether, butyl propyl ether, dibutyl ether, diisobutyl ether,tert-butyl methyl ether,tert-butyl ethyl ether, tert-butyl propyl ether, di-tert-butyl ether,dipentyl ether, diisoamyl ether, dihexyl ether, dioctyl ether,cyclopentyl methyl ether,cyclohexyl methyl ether, cyclododecyl methyl ether, cyclopentyl ethylether, cyclohexyl ethyl ether, cyclopentyl propyl ether, cyclopentyl2-propyl ether, cyclohexyl propyl ether, cyclohexyl 2-propyl ether,cyclopentyl butyl ether, cyclopentyl-tert-butyl ether, cyclohexyl butylether, cyclohexyl-tert-butyl ether, bromomethyl methyl ether,iodomethyl methyl ether, α,α-dichloromethyl methyl ether, chloromethylethyl ether, 2-chloroethyl methyl ether, 2-bromoethyl methyl ether,2,2-dichloroethyl methyl ether, 2-chloroethyl ethyl ether, 2-bromoethylethyl ether, (±)-1,2-dichloroethyl ethyl ether,di-2-bromoethyl ether, 2,2,2-trifluoroethyl ether, chloromethyl octylether, bromomethyl octyl ether, di-2-chloroethyl ether, ethyl vinylether, butyl vinyl ether, aryl ethyl ether, aryl propyl ether, arylbutyl ether, diaryl ether, 2-methoxypropene, ethyl-1-propenyl ether,1-methoxy-1,3-butadiene, cis-1-bromo-2-ethoxyethylene, 2-chloroethylvinyl ether, and aryl-1,1,2,2-tetrafluoroethyl ether can be given.Examples of preferable ethers include dipropyl ether, diisopropyl ether,butyl methyl ether, butyl ethyl ether, butyl propyl ether, dibutylether, diisobutyl ether, tert-butyl-methyl ether, tert-butyl ethylether, tert-butyl propyl ether, di-tert-butyl ether, dipentyl ether,diisoamyl ether, cyclopentyl methyl ether, cyclohexyl methyl ether,cyclopentyl ethyl ether, cyclohexyl ethyl ether, cyclopentyl propylether, cyclopentyl-2-propyl ether, cyclohexyl propyl ether,cyclohexyl-2-propyl ether, cyclopentyl butyl ether,cyclopentyl-tert-butyl ether, cyclohexyl butyl ether, andcyclohexyl-tert-butyl ether.

The above ethers are used in combination with other solvents. Asexamples of the solvents used with the above ethers, monohydricalcohols, polyhydric alcohols, cyclic ethers, alkyl ethers of polyhydricalcohols, alkyl ether acetates of polyhydric alcohols, aromatichydrocarbons, ketones, esters, water, and the like can be given.

Examples of monohydric alcohols include methanol, ethanol, 1-propanol,isopropanol, n-propanol, 2-methyl-1-propanol, n-butanol, 2-butanol,tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, n-hexanol,cyclohexanol, 2-methyl-2-butanol, 3-methyl-2-butanol,2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-1-pentanol,

2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol,3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol,4-methyl-2-pentanol, 2-ethyl-1-butanol, 2,2-dimethyl-3-pentanol,2,3-dimethyl-3-pentanol, 2,4-dimethyl-3-pentanol,4,4-dimethyl-2-pentanol, 3-ethyl-3-pentanol, 1-heptanol, 2-heptanol,3-heptanol, 2-methyl-2-hexanol, 2-methyl-3-hexanol, 5-methyl-1-hexanol,5-methyl-2-hexanol, 2-ethyl-1-hexanol, methylcyclohexanol,trimethylcyclohexanol, 4-methyl-3-heptanol, 6-methyl-2-heptanol,1-octanol, 2-octanol, 3-octanol, 2-propyl-1-pentanol,2,4,4-trimethyl-1-pentanol,2,6-dimethyl-4-heptanol, 3-ethyl-2,2-dimethyl-pentanol, 1-nonanol,2-nonanol, 3,5,5-trimethyl-1-hexanol, 1-decanol, 2-decanol, 4-decanol,3,7-dimethyl-1-octanol, and 3,7-dimethyl-3-octanol.

Among the monohydric alcohols, monohydric alcohols having 4 to 8 carbonatoms are preferable. Specifically, 2-methyl-1-propanol, 1-butanol,2-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 3-methyl-2-pentanol,4-methyl-2-pentanol, 2-ethyl-1-butanol, 2,4-dimethyl-3-pentanol arepreferable.

Examples of the polyhydric alcohols include ethylene glycol andpropylene glycol. Examples of the cyclic ethers include tetrahydrofuranand dioxane. Examples of the alkyl ethers of polyhydric alcohol includeethylene glycol monomethyl ether, ethylene glycol monoethyl ether,ethylene glycol dimethyl ether, ethylene glycol diethyl ether,diethylene glycol monomethyl ether, diethylene glycol monoethyl ether,diethylene glycol dimethyl ether, diethylene glycol diethyl ether,diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether,and propylene glycol monoethyl ether. Examples of the alkyl etheracetates of polyhydric alcohol include ethylene glycol ethyl etheracetate, diethylene glycol ethyl ether acetate, propylene glycol ethylether acetate, and propylene glycol monomethyl ether acetate. Examplesof the aromatic hydrocarbons include benzene, toluene, and xylene.Examples of the ketones include acetone, methyl ethyl ketone, methylisobutyl ketone, cyclohexanone,

4-hydroxy-4-methyl-2-pentanone, and diacetone alcohol. Examples of theesters include ethyl acetate, butyl acetate, ethyl 2-hydroxypropionate,methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate,ethyl ethoxyacetate, ethyl hydroxyacetate, methyl2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl3-methoxypropionate, ethyl 3-ethoxypropionate, and methyl3-ethoxypropionate.

Of these, the monohydric alcohols, cyclic ethers, alkyl ethers ofpolyhydric alcohols, alkyl ether acetates of polyhydric alcohols,ketones, esters, and water are preferable, with the monohydric alcoholsbeing more preferable.

When the above ethers are used with the other solvents, it is preferablethat the amount of the other solvents be not more than 75 wt % of theentire solvent. If the amount of the other solvents is not more than 75wt %, not only the viscosity of the mixed solvent at 20° C. can becontrolled to less than 5.2×10⁻³ Pa·s, and preferably in a range of0.7×10⁻³ Pa·s to 4.0×10⁻³ Pa·s, but also the amount of the upperlayer-forming composition to be homogeneously applied on a silicon wafercan be decreased and elusion of anionic components from the compositioncan be further suppressed.

The solvent used in the embodiment of the present invention does notcause intermixing between the photoresist film and the upperlayer-forming composition.

Some solvents, for example, tetrahydrofuran, propylene glycol monomethylether acetate, methyl ethyl ketone, and the like which may corrode aresist film and cause intermixing if used alone are preferably usedunder the conditions which the solvent is judged not to causeintermixing when evaluated according to the later-described evaluationmethod. These solvents are used in an amount of 30 wt % or less, andpreferably 20 wt % or less of the total amount of the solvents used. Ifmore than 30 wt %, the photoresist film may be corroded and may causeintermixing with the upper layer film, leading to significantdeterioration of resolution performance of the photoresist.

As examples of preferable solvents used in the embodiment of the presentinvention, a mixture of an ether of the formula (1) in which R¹ and R²individually represent hydrocarbon groups having 1 to 8 carbon atoms anda monohydric alcohol having 4 to 8 carbon atoms can be given.

The resin which constitutes the upper layer-forming composition of theembodiment is a resin capable of forming a film stable to a medium suchas water during exposure to radiation and dissolvable in the developerused for forming a resist pattern.

The term “film stable in a medium such as water during exposure toradiation” indicates a film of which the thickness change when measuringby a stability evaluation method in water mentioned later, for example,is not more than 3% of the initial film thickness.

The term “dissolvable in the developer used for forming a resistpattern” indicates the upper layer film can be removed to the extentthat there is no residue observed by the naked eye on the resist patternafter development using an alkaline aqueous solution. That is to say,the resin used in the embodiment has almost no solubility in a mediumsuch as water, but is dissolved in the alkaline aqueous solution usedfor developing the photoresist pattern after exposure to radiation (sucha resin of the embodiment is hereinafter referred to as “alkali-solubleresin”).

The upper layer film made from such an alkali-soluble resin inhibits thephotoresist film from coming in direct contact with the medium such aswater during the liquid immersion lithography, thereby preventing thephotoresist film from reducing the lithographic performance due topenetration of the medium and also preventing the lens of the projectionaligner from being polluted with components eluted from the photoresistfilm.

The resin contains at least one recurring unit selected from a groupconsisting of a recurring unit having a group shown by the followingformula (2), a recurring unit having a group shown by the followingformula (3), a recurring unit having a group shown by the followingformula (4), a recurring unit having a carboxyl group, and a recurringunit having a sulfo group. These recurring units can be incorporated inthe resin by polymerizing a radically-polymerizable monomer whichcontains these units and a polymerizable unsaturated bond.

In the recurring unit having a group shown by the formula (2), examplesof the alkyl group having 1 to 4 carbon atoms include a methyl group, anethyl group, a propyl group, and a butyl group, and examples of thefluoroalkyl group having 1 to 4 carbon atoms include a difluoromethylgroup, a perfluoromethyl group, a 2,2-difluoroethyl group, a2,2,2-trifluoroethyl group, a perfluoroethyl group, a2,2,3,3,-tetrafluoropropyl group, a perfluoroethylmethyl group, aperfluoropropyl group, a 2,2,3,3,4,4-hexafluorobutyl group, aperfluorobutyl group, a 1,1-dimethyl-2,2,3,3-tetrafluoropropyl group,and the like.

Of these groups, a perfluoromethyl group is preferable.

The recurring unit having a group shown by the formula (2) is arecurring unit having an alcoholic hydroxyl group which contains on theside chain at least one fluoroalkyl group on at least α-position carbonatom. The hydrogen atom of the alcoholic hydroxyl group is easilyreleased due to electron withdrawing properties of a fluoroalkyl group,particularly a perfluoromethyl group. As a result, the resin exhibitsacidity in an aqueous solution. Therefore, the resin is insoluble inpure water, but soluble in alkali.

The recurring unit shown by the following formula (2a) can be given as apreferable example of the recurring unit having the group shown by theformula (2).

wherein R represents a hydrogen atom or a methyl group, and R⁷represents an organic group, and preferably a divalent hydrocarbongroup. Linear hydrocarbon groups and cyclic hydrocarbon groups arepreferable among the divalent hydrocarbon group.

Preferable examples of R⁷ include a methylene group; an ethylene group;a propylene group such as a 1,3-propylene group and a 1,2-propylenegroup; a saturated linear hydrocarbon group such as a tetramethylenegroup, a pentamethylene group, a hexamethylene group, a heptamethylenegroup, an octamethylene group, a nonamethylene group, a decamethylenegroup, an undecamethylene group, a dodecamethylene group, atridecamethylene group, a tetradecamethylene group, a pentadecamethylenegroup, a hexadecamethylene group, a heptadecamethylene group, anoctadecamethylene group, a nonadecamethylene group, an icosa methylenegroup, a 1-methyl-1,3-propylene group, a 2-methyl-1,3-propylene group, a2-methyl-1,2-propylene group, a 1-methyl-1,4-butylene group, a2-methyl-1,4-butylene group, a methylidene group, an ethylidene group, apropylidene group, and a 2-propylidene group; a monocyclic hydrocarbonring group, such as a cycloalkylene group having 3 to 10 carbon atoms,for example, a cyclobutylene group such as a 1,3-cyclobutylene group, acyclopentylene group such as a 1,3-cyclopentylene group, a cyclohexylenegroup such as a 1,4-cyclohexylene group, and a cyclooctylene group suchas a 1,5-cyclooctylene group; crosslinked cyclic hydrocarbon ring groupssuch as a cyclic hydrocarbon group having 2 to 4 rings and 4 to 30carbon atoms, for example, a norbornylene group such as a1,4-norbornylene group and 2,5-norbornylene group, and an adamantylenegroup such as 1,5-adamantylene group, and 2,6-adamantylene group, andthe like.

Particularly when the R⁷ is a divalent alicyclic hydrocarbon group, itis preferable to insert an alkylene group having 1 to 4 carbon atoms asa spacer between the bis(trifluoromethyl)hydroxymethyl group and thealicyclic hydrocarbon group.

Preferable groups represented by R⁷ in the formula (2a) are ahydrocarbon group having a 2,5-norbornylene group or a 2,6-norbornylenegroup, and a 1,2-propylene group.

In the recurring unit having a group shown by the formula (3), examplesof the fluoroalkyl group having 1 to 20 carbon atoms represented by R⁵include a fluoroalkyl group having 1 to 20 carbon atoms such as adifluoromethyl group, a perfluoromethyl group, a 2,2-difluoroethylgroup, a 2,2,2-trifluoroethyl group, a perfluoroethyl group, a2,2,3,3,-tetrafluoropropyl group, a perfluoroethylmethyl group, aperfluoropropyl group, a 2,2,3,3,4,4-hexafluorobutyl group, aperfluorobutyl group, a 1,1-dimethyl-2,2,3,3-tetrafluoropropyl group, a1,1-dimethyl-2,2,3,3,3-pentafluoropropyl group, a2-(perfluoropropyl)ethyl group, a 2,2,3,3,4,4,5,5-octafluoropentylgroup, a perfluoropentyl group, a1,1-dimethyl-2,2,3,3,4,4-hexafluorobutyl group, a1,1-dimethyl-2,2,3,3,4,4,4-heptafluorobutyl group, a2-(perfluorobutyl)ethyl group, a 2,2,3,3,4,4,5,5,6,6-decafluorohexylgroup, a perfluoropentylmethyl group, a perfluorohexyl group, a1,1-dimethyl-2,2,3,3,4,4,5,5-octafluoropentyl group, a1,1-dimethyl-2,2,3,3,4,4,5,5,5-nonafluoropentyl group, a2-(perfluoropentyl)ethyl group, a2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl group, a perfluorohexylmethylgroup, a perfluoroheptyl group, a 2-(perfluorohexyl)ethyl group, a2,2,3,3,4,4,5,5,6,6,7,7,8,8-tetradecafluorooctyl group, aperfluoroheptylmethyl group, a perfluorooctyl group, a2-(perfluoroheptyl)ethyl group, a2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluorononyl group, aperfluorooctylmethyl group, a perfluorononyl group, a2-(perfluorooctyl)ethyl group, a2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-octadecafluorodecyl group, aperfluorononylmethyl group, a perfluorodecyl group, a2,2,3,4,4,4-hexafluorobutyl group, a 2,2,3,3,4,4,4-heptafluorobutylgroup, a 3,3,4,4,5,5,6,6,6-nonafluorohexyl group, a3,3,4,4,5,5,6,6,7,7,8,8,8-tridodecafluorooctyl group, and the like.

Of these, a perfluoromethyl group, a perfluoroethyl group, aperfluoropropyl group, a perfluorobutyl group, and a perfluorooctylgroup are particularly preferable in order to have the appropriateacidity of the hydrogen bonded to the nitrogen atom.

The recurring unit shown by the following formula (3a) can be given as apreferable example of the recurring unit having the group shown by theformula (3).

wherein R represents a hydrogen atom or a methyl group, and R⁵ is thesame as the R⁵ in the formula (3).

R⁸ represents an organic group, and preferably a divalent hydrocarbongroup. Linear hydrocarbon groups and cyclic hydrocarbon groups arepreferable among the divalent hydrocarbon group.

Preferable examples of R⁸ include a methylene group; an ethylene group;a propylene group such as a 1,3-propylene group and a 1,2-propylenegroup; an unsaturated linear hydrocarbon group such as a tetramethylenegroup, a pentamethylene group, a hexamethylene group, a heptamethylenegroup, an octamethylene group, a nonamethylene group, a decamethylenegroup, an undecamethylene group, a dodecamethylene group, atridecamethylene group, a tetradecamethylene group, a pentadecamethylenegroup, a hexadecamethylene group, a heptadecamethylene group, anoctadecamethylene group, a nonadecamethylene group, an icosa methylenegroup, a 1-methyl-1,3-propylene group, a 2-methyl-1,3-propylene group, a2-methyl-1,2-propylene group, a 1-methyl-1,4-butylene group, a2-methyl-1,4-butylene group, a methylidene group, an ethylidene group, apropylidene group, and a 2-propylidene group; a monocyclic hydrocarbonring group, such as a cycloalkylene group having 3 to 10 carbon atoms,for example, a cyclobutylene group such as a 1,3-cyclobutylene group, acyclopentylene group such as a 1,3-cyclopentylene group, a cyclohexylenegroup such as a 1,4-cyclohexylene group, and a cyclooctylene group suchas a 1,5-cyclooctylene group; crosslinked cyclic hydrocarbon groups suchas a cyclic hydrocarbon group having 2 to 4 rings and 4 to 30 carbonatoms, for example, a norbornylene group such as a 1,4-norbornylenegroup and 2,5-norbornylene group, and an adamantylene group such as1,5-adamantylene group and 2,6-adamantylene group; and the like.

Particularly when the R⁸ is a divalent alicyclic hydrocarbon group, analkylene group having 1 to 4 carbon atoms may be inserted as a spacerbetween an —NH— group and the alicyclic hydrocarbon group.

As R⁸, a hydrocarbon group having a 2,5-norbornylene group or a1,5-adamantylene group, an ethylene group, and a 1,3-propylene group arepreferable.

In the recurring unit having a group shown by the formula (4), R⁶represents an organic group having a polar group, preferably ahydrocarbon group having a monovalent polar group having 1 to 20 carbonatoms or a fluorinated hydrocarbon group.

The recurring unit shown by the following formula (4a) can be given as apreferable example of the recurring unit having the group shown by theformula (4).

wherein R represents a hydrogen atom or a methyl group, and R⁶represents a residue of an alcohol which forms an ester bond with(meth)acrylic acid and has a polar group.

Examples of preferable R⁶ include a hydroxymethyl group, a1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a2-hydroxypropyl group, a 3-hydroxypropyl group, a 2-hydroxybutyl group,a 2,3-dihydroxypropyl group, a polypropyleneglycol group, a2-hydroxycyclohexyl group, a 4-hydroxycyclohexyl group, a3-hydroxy-1-adamantyl group, a 3,5-dihydroxy-1-adamantyl group, anaminomethyl group, a 1-aminoethyl group, a 2-aminoethyl group, a1-aminopropyl group, a 2-aminopropyl group, a 3-aminopropyl group, a2,3-dihydroxypropyl group, a 1,2,3-trihydroxypropyl group, adifluoromethyl group, a perfluoromethyl group, a 2,2-difluoroethylgroup, a 2,2,2-trifluoroethyl group, a perfluoroethyl group, a1-(perfluoromethyl)ethyl group, a 2-(perfluoromethyl)ethyl group, a2,2,3,3-tetrafluoropropyl group, a perfluoroethylmethyl group, adi(perfluoromethyl)methyl group, a perfluoropropyl group, a1-methyl-2,2,3,3-tetrafluoropropyl group, a 1-(perfluoroethyl)ethylgroup, a 2-(perfluoroethyl)ethyl group, a 2,2,3,3,4,4-hexafluorobutylgroup, a perfluoropropylmethyl group, a perfluorobutyl group, aperfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group,a perfluorooctyl group, a perfluorononyl group, a perfluorodecyl group,a (2,2,2-trifluoroethyl)α-carboxyl group, a(perfluoroethylmethyl)α-carboxyl group, a(2,2,2-trifluoroethyl)α-carboxymethyl group, a(2,2,2-trifluoroethyl)α-cyano group, a (perfluoroethylmethyl)α-cyanogroup, a (2,2,3,3,3-pentafluoropropyl)-2-ethoxy group, a(2,2,3,3,3-pentafluoropropyl)-2-cyano group.

As examples of the radical polymerizable monomer generating a recurringunit having a carboxyl group, unsaturated monocarboxylic acids such as(meth)acrylic acid, crotonic acid, cinnamic acid, atropic acid,3-acetyloxy(meth)acrylate, 3-benzoiloxy(meth)acrylate,α-methoxyacrylate, 3-cyclohexyl(meth)acrylate; unsaturatedpolycarboxylic acids such as fumaric acid, maleic acid, citraconic acid,mesaconic acid, itaconic acid; monoesters (e.g., monomethyl ester,monoethyl ester, mono-n-propyl ester, and mono-n-butyl ester) of theunsaturated polycarboxylic acids;2-(meth)acrylamide-2-methylpropanecarboxylic acid,2-α-carboxyacrylamide-2-methylpropanecarboxylic acid,2-α-carboxymethylacrylamide-2-methylpropanecarboxylic acid,2-α-methoxycarbonylacrylamide-2-methylpropanecarboxylic acid,2-α-acetyloxyacrylamide-2-methylpropanecarboxylic acid,2-α-phenylacrylamide-2-methylpropanecarboxylic acid,2-α-benzylacrylamide-2-methylpropanecarboxylic acid,2-α-methoxyacrylamide-2-methylpropanecarboxylic acid,2-α-cyclohexylacrylamide-2-methylpropanecarboxylic acid,2-α-cyanoacrylamide-2-methylpropanecarboxylic acid, and the like can begiven.

Among the above monomers, (meth)acrylic acid and crotonic acid arepreferable.

As the recurring unit having a carboxyl group, a radical polymerizablemonomer shown by the formula (5) can be given.

wherein R represents a hydrogen atom or a methyl group, A represents asingle bond, a carbonyl group, a carbonyloxy group, and an oxycarbonylgroup, and B represents a single bond and a divalent organic grouphaving 1 to 20 carbon atoms. Examples of the divalent organic grouphaving 1 to 20 carbon atoms include a methylene group; an ethylenegroup; a propylene group such as a 1,3-propylene group and a1,2-propylene group; an unsaturated linear hydrocarbon group such as atetramethylene group, a pentamethylene group, a hexamethylene group, aheptamethylene group, an octamethylene group, a nonamethylene group, adecamethylene group, an undecamethylene group, a dodecamethylene group,a tridecamethylene group, a tetradecamethylene group, apentadecamethylene group, a hexadecamethylene group, aheptadecamethylene group, an octadecamethylene group, anonadecamethylene group, an icosa methylene group, a1-methyl-1,3-propylene group, a 2-methyl-1,3-propylene group, a2-methyl-1,2-propylene group, a 1-methyl-1,4-butylene group, a2-methyl-1,4-butylene group, a methylidene group, an ethylidene group, apropylidene group and a 2-propylidene group; a monocyclic hydrocarbonring group, such as an arylene group such as a phenylene group and atolylene group, a cycloalkylene group having 3 to 10 carbon atoms, forexample, a cyclobutylene group such as a 1,3-cyclobutylene group, acyclopentylene group such as a 1,3-cyclopentylene group, a cyclohexylenegroup such as a 1,4-cyclohexylene group, and a cyclooctylene group suchas a 1,5-cyclooctylene group; crosslinked cyclic hydrocarbon groups suchas a cyclic hydrocarbon group having 2 to 4 rings and 4 to 20 carbonatoms, for example, a norbornylene group such as a 1,4-norbornylenegroup and 2,5-norbornylene group, and an adamantylene group such as1,5-adamantylene group and 2,6-adamantylene group; and the like.

The radically polymerizable monomers generating the recurring unithaving a sulfo group is shown by the following formula (6).

In the formula (6), A and B are the same as those defined for theformula (5). The formula (6) can be obtained by replacing the carboxylgroup in the formula (5) with a sulfo group.

Preferable examples of the monomer shown by the formula (6) includevinylsulfonic acid, allylsulfonic acid,2-(meth)acrylamide-2-methyl-1-propanesulfonic acid, and4-vinyl-1-benzenesulfonic acid. Of these sulfonic acid monomers,vinylsulfonic acid and allylsulfonic acid are particularly preferable.

The resin component of the upper layer-forming composition of theembodiment contains at least one recurring unit selected from a groupconsisting of a recurring unit having a group shown by the above formula(2), a recurring unit having a group shown by the above formula (3), arecurring unit having a group shown by the above formula (4), arecurring unit having a carboxyl group, and a recurring unit having asulfo group.

In addition, other radically-polymerizable monomers may be copolymerizedwith the resin component of the upper layer-forming composition of theembodiment in order to control the molecular weight, the glasstransition temperature, solubility in solvents, and the like of theresin. The “Other monomers” indicate radically polymerizable monomersother than the above-mentioned radically polymerizable monomers. Inaddition, an acid-dissociable group-containing monomer may becopolymerized.

As examples of the other radically-polymerizable monomer oracid-dissociable group-containing monomer, (meth)acrylic acid alkylesters such as methyl(meth)acrylate, ethyl(meth)acrylate,n-butyl(meth)acrylate, sec-butyl(meth)acrylate,tert-butyl(meth)acrylate, isopropyl(meth)acrylate,n-hexyl(meth)acrylate, cyclohexyl(meth)acrylate,2-methylcyclohexyl(meth)acrylate, dicyclopentanyloxyethyl(meth)acrylate,isobornyl(meth)acrylate, dicyclopentanyl(meth)acrylate,methoxydipropyleneglycol(meth)acrylate,butoxy-dipropyleneglycol(meth)acrylate,methoxydiethyleneglycol(meth)acrylate,methoxypropyleneglycol(meth)acrylate,2-methyl-2-adamantyl(meth)acrylate, 2-ethyl-2-adamantyl(meth)acrylate,2-propyl-2-adamantyl(meth)acrylate, 2-butyl-2-adamantyl(meth)acrylate,1-methyl-1-cyclohexyl(meth)acrylate, 1-ethyl-1-cyclohexyl(meth)acrylate,1-propyl-1-cyclohexyl(meth)acrylate, 1-butyl-1-cyclohexyl(meth)acrylate,1-methyl-1-cyclopentyl(meth)acrylate,1-ethyl-1-cyclopentyl(meth)acrylate,1-propyl-1-cyclopentyl(meth)acrylate,1-butyl-1-cyclopentyl(meth)acrylate,1-adamantyl-1-methylethyl(meth)acrylate, and1-bicyclo[2.2.1]heptyl-1-methylethyl(meth)acrylate; dicarboxylic aciddiesters such as maleic acid diesters, fumaric acid diesters, anditaconic acid diesters; (meth) acrylic acid aryl esters such asphenyl(meth)acrylate and benzyl(meth)acrylate; aromatic vinyl esterssuch as stylene, α-methylstylene, m-methylstylene, p-methylstylene,vinyl toluene, p-methoxystylene; radical polymerizable monomers having anitrile group such as acrylonitril and methacrylonitrile; radicalpolymerizable monomers having an amide bond such as acrylamide andmethacrylamide; fatty acid vinyl esters such as vinyl acetate; radicalpolymerizable monomers having a chlorine atom such as vinyl chloride andvinylidene chloride; and conjugated diolefins such as 1,3-butadiene,isoprene and 1,4-dimethylbutadiene can be given. Of these, (meth)acrylicacid alkyl esters, radical polymerizable monomers having a nitrilegroup, radical polymerizable monomers having an amide bond, and(meth)acrylic acid alkyl esters having a hydroxyl group are preferable.

These monomers may be used either individually or in combination of twoor more.

When copolymerized with the other radically-polymerizable monomers, theproportion of the other radically-polymerizable monomers is preferably50 mol % or less, and more preferably 40 mol % or less of the totalamount of the polymer. If more than 50 mol %, the solubility of theresin in an alkaline developer is decreased. Since it is difficult toremove the upper layer film, a residue may remain on the resist patternafter development.

As examples of the polymerization solvents used for preparing thealkali-soluble resins, alcohols such as methanol, ethanol, 1-propanol,2-propanol, 1-butanol, 2-butanol, ethylene glycol, diethylene glycol,and propylene glycol; cyclic ethers such as tetrahydrofuran and dioxane;alkyl ethers of polyhydric alcohol such as ethylene glycol monomethylether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether,ethylene glycol diethyl ether, diethylene glycol monomethyl ether,diethylene glycol monoethyl ether, diethylene glycol dimethyl ether,diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether,propylene glycol monomethyl ether, and propylene glycol monoethyl ether;alkyl ether acetates of polyhydric alcohol such as ethylene glycol ethylether acetate, diethylene glycol ethyl ether acetate, propylene glycolethyl ether acetate, and propylene glycol monomethyl ether acetate;aromatic hydrocarbons such as toluene and xylene; ketones such asacetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone,4-hydroxy-4-methyl-2-pentanone, and diacetone alcohol; esters such asethyl acetate, butyl acetate, methyl-2-hydroxypropionate,ethyl-2-hydroxy-2-methylpropionate, ethyl-2-hydroxy-2-methylpropionate,ethoxy ethyl acetate, hydroxy ethyl acetate,methyl-2-hydroxy-3-methylbutanate, methyl-3-methoxypropionate,ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, andmethyl-3-ethoxypropionate can be given. Of these, cyclic ethers, alkylether of polyhydric alcohol, alkyl ether acetates of polyhydric alcohol,ketones, and esters are preferable.

A commonly used radical polymerization initiator can be used as thepolymerization catalyst in the radical copolymerization. As examples,azo compounds such as 2,2′-azobisisobutyronitrile,2,2′-azobis-(2-methylmethylpropionate),2,2′-azobis-(2,4-dimethylvaleronitrile),2,2′-azobis-(4-methoxy-2-dimethylvaleronitrile); organic peroxides suchas benzoyl peroxide, lauroyl peroxide, tert-butylperoxypivalate,

1,1′-bis-(tert-butylperoxy)cyclohexane; and hydrogen peroxide can begiven. When using a peroxide as the radical polymerization initiator, areducing agent may be combined to form a redox-type initiator.

The polystyrene-reduced weight average molecular weight (hereinafterreferred to as “Mw”) of the alkali-soluble resin obtained by the abovemethod determined by gel permeation chromatography is generally 2,000 to100,000, preferably 2,500 to 50,000, and more preferably 3,000 to20,000. If Mw of the alkali-soluble resin is less than 2,000, waterresistance and mechanical properties of the upper layer film is undulylow; if more than 100,000, the solubility in the above-mentionedsolvents is significantly low. The ratio of Mw to thepolystyrene-reduced number average molecular weight (hereinafterreferred to as “Mn”) of the resin determined by gel permeationchromatography (GPC) (Mw/Mn) of the copolymer is usually from 1 to 5,and preferably from 1 to 3.

It is preferable that the resin contains impurities such as halogens ormetals in an amount as small as possible. The smaller the amount ofimpurities is, the further it can improve applicability as an upperlayer film and the properties of being homogeneously dissolved in analkaline developer. As a purification method of the resin, a chemicalpurification method such as washing with water or liquid-liquidextraction and a combination of such a chemical purification method anda physical purification method such as ultrafiltration, centrifugation,or the like can be given. In the embodiment of the present invention,the resins can be used either individually or in combination of two ormore.

A surfactant can be blended with the upper layer-forming composition forimmersion lithography of the embodiment in order to increaseapplicability, defoamability, leveling properties, and the like.

As a surfactant, fluorine-containing surfactants commercially availableunder the trade names of “BM-1000” and “BM-1100” (manufactured by BMCHEMIE Co., Ltd.), “MEGAFAC F142D”, “MEGAFAC F172”, “MEGAFAC F173”, and“MEGAFAC F183” (manufactured by Dainippon Ink and Chemicals, Inc.),“Fluorad FC-135”, “Fluorad FC-170C”, “Fluorad FC-430”, and “FluoradFC-431 (manufactured by Sumitomo 3M), “Surflon S-112” “Surflon S-113”,“Surflon S-131”, “Surflon S-141”, and “Surflon S-145” (manufactured byAsahi Glass Co., Ltd.), “SH-28PA”, “SH-190”, “SH-193”, “SZ-6032”, and“SF-8428” (manufactured by Dow Corning Toray Silicone Co., Ltd.), andthe like can be used.

The amount of surfactants to be added is preferably 5 parts by weight orless for 100 parts by weight of the alkali-soluble resin.

In addition, a low molecular compound such as a radiation-sensitive acidgenerator (hereinafter referred to as “acid generator”), an acid, andthe like may be added to the upper layer-forming composition forimmersion lithography of the embodiment in order to increase lithographyperformance of the resist.

As examples of the acid generator, (1) a sulfonimide compound, (2) adisulfonyl methane compound, (3) an onium salt compound, (4) a sulfonecompound, (5) a sulfonate compound, (6) a diazomethane compound, and thelike can be given.

Examples of these acid generators are given below.

(1) Sulfonimide Compounds

As examples of the sulfonimide compounds, compounds of the followingformula (7) can be given,

wherein R¹⁰ is a monovalent organic group and R⁹ is a divalent organicgroup.

The monovalent organic group includes a substituted or unsubstitutedlinear or branched alkyl group, a substituted or unsubstituted cyclicalkyl group, a substituted or unsubstituted aryl group, a perfluoroalkylgroup, and the like, and the divalent organic group includes asubstituted or unsubstituted alkylene group, a substituted orunsubstituted alkenylene group, a substituted or unsubstituted phenylenegroup, and the like.

As examples of the sulfonimide compound,N-(trifluoromethylsulfonyloxy)succineimide,N-(trifluoromethylsulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide,N-(10-camphorsulfonyloxy)succineimide,N-(10-camphorsulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide,N-(camphorsulfonyloxy)-7-oxabicyclo[2.2.1]hept-5-ene-dicarboxyimide,N-(p-toluenesulfonyloxy)succineimide,N-(p-toluenesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxy imide,N-(4-trifluoromethylbenzenesulfonyloxy)succineimide,N-(4-trifluoromethylbenzenesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylmide,N-(perfluorobenzenesulfonyloxy)succineimide,N-(perfluorobenzenesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylmide, N-(nonafluorobutylsulfonyloxy)succineimide,N-(nonafluorobutylsulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide,N-(perfluorooctanesulfonyloxy)succineimide,N-(perfluorooctanesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide,N-(benzenesulfonyloxy)succineimide,N-(benzenesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylmide,N-(benzenesulfonyloxy)-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide,andN-{(5-methyl-5-carboxymethanebicyclo[2.2.1]hept-2-yl)sulfonylocxy}succineimidecan be given.

(2) Disulfonylmethane Compounds

As examples of the disulfonylmethane compounds, compounds of thefollowing formula (8) can be given,

wherein R¹¹ and R¹² individually represent a linear or branchedmonovalent aliphatic hydrocarbon group, a cycloalkyl group, an arylgroup, an aralkyl group, or another monovalent organic group having ahetero atom, and V and W individually represents an aryl group, ahydrogen atom, a linear or branched monovalent aliphatic hydrocarbongroup, or another monovalent organic group having a hetero atom, whereinat least one of V and W is an aryl group, V and W bond to form amonocyclic or polycyclic ring having at least one unsaturated bond, or Vand W bond to form a group shown by the following formula (8-1),

wherein V′ and W′ individually represent a hydrogen atom, a halogenatom, a linear or branched alkyl group, a cycloalkyl group, an arylgroup, or an aralkyl group, or V′ and W′ bonding to the same carbon atomor different carbon atoms bond together to form a monocyclic hydrocarbonstructure (in the case that there are two or more V's and W's, the V'sand W's may be either the same or different), and r is an integer of 2to 10.

(3) Onium Salt Compound

As examples of the onium salt, an iodonium salt, a sulfonium salt, aphosphonium salt, a diazonium salt, an ammonium salt, and a pyridiniumsalt can be given.

Specific examples of the onium salt compound includebis(4-t-butylphenyl)iodonium nonafluorobutanesulfonate,bis(4-t-butylphenyl)iodonium trifluorobutanesulfonate,bis(4-t-butylphenyl)iodonium perfluorooctanesulfonate,bis(4-t-butylphenyl)iodonium p-toluenesulfonate,bis(4-t-butylphenyl)iodonium 10-camphorsulfonate,4-trifluoromethylbenzenesulfonate, bis(4-t-butylphenyl)iodoniumperfluorobenzenesulfonate, diphenyliodonium nonafluorobutanesulfonate,diphenyliodonium trifluoromethanesulfonate, diphenyliodoniumperfluorooctanesulfonate, diphenyliodonium p-toluenesulfonate,diphenyliodoniumbenzenesulfonate, diphenyliodonium 10-camphorsulfonate,diphenyliodonium-4-trifluoromethylbenzenesulfonate, diphenyliodoniumperfluorobenzenesulfonate, triphenylsulfonium nonafluorobutanesulfonate,triphenylsulfonium trifluoromethanesulfonate, triphenylsulfoniumperfluorooctanesulfonate, triphenylsulfonium p-toluenesulfonate,triphenylsulfoniumbenzenesulfonate, triphenylsulfonium10-camphorsulfonate, triphenylsulfonium4-trifluoromethylbenzenesulfonate, triphenylsulfoniumperfluorobenzenesulfonate, 4-hydroxyphenyl diphenylsulfoniumtrifluoromethanesulfonate, tri(p-methoxyphenyl)sulfoniumnonafluorobutanesulfonate, tri(p-methoxyphenyl)sulfoniumtrifluorofluoromethanesulfonate, tri(p-methoxyphenyl)sulfoniumperfluorooctanesulfonate, tri(p-methoxyphenyl)sulfoniump-toluenesulfonate, tri(p-methoxyphenyl)sulfonium benzenesulfonate,tri(p-methoxyphenyl)sulfonium 10-camphorsulfonate,bis(p-fluorophenyl)iodonium trifluoromethanesulfonate,bis(p-fluorophenyl)iodonium nonafluoromethanesulfonate,bis(fluorophenyl)iodonium camphorsulfonate,(p-fluorophenyl)(phenyl)iodonium trifluoromethanesulfonate,tris(p-fluorophenyl)sulfonium trifluoromethanesulfonate,tris(p-fluorophenyl)sulfonium p-toluenesulfonate,(p-fluorophenyl)diphenylsulfonium trifluoromethanesulfonate,1-(4-n-buthoxynaphthyl)tetrahydrophenium nonafluoro-2-butanesulfonate,triphenylsulfonium1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodecane-8-yl)ethanesulfonate,triphenylsulfonium1,1-difluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodecane-8-yl)ethanesulfonate,1-(4-n-butoxynaphthyl)tetrahydrophenium1,1,2,2-tetrafluoro2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodecane-8-yl)ethanesulfonate,and 1-(4-n-butoxynaphthyl)tetrahydrophenium1,1-difluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodecane-8-yl)ethanesulfonate.

(4) Sulfone Compound

As examples of the sulfone compounds, β-ketosulfone, β-sulfonylsulfone,an α-diazo compound of these compounds, and the like can be given.

As specific examples of the sulfone compound, phenacylphenylsulfone,mesitylphenacylsulfone, bis(phenylsulfonyl)methane,4-trisphenacylsulfone, and the like can be given.

(5) Sulfonate Compounds

As examples of sulfonate compounds, an alkyl sulfonate, a haloalkylsulfonate, an aryl sulfonate, an imino sulfonate, and the like can begiven.

As specific examples of the sulfonate compounds, benzointosylate,pyrogalloltris(trifluoromethanesulfonate),pyrogalloltris(nonafluoro-2-butanesulfonate),pyrogalloltris(methanesulfonate),nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate,α-methylolbenzointosylate, α-methylolbenzoin n-octanesulfonate,α-methylolbenzointrifluoromethanesulfonate, and α-methylolbenzoinn-decanesulfonate can be given.

(6) Diazomethane Compounds

As examples of the diazomethane compounds, compounds shown by thefollowing formula (9) can be given;

wherein R¹³ and R¹⁴ individually represent a monovalent group such as analkyl group, an aryl group, a haloalkyl group, and a haloaryl group.

As examples of the diazomethane compounds,bis(trifluoromethanesulfonyl)diazomethane,bis(cyclohexanesulfonyl)diazomethane, bis(benzenesulfonyl)diazomethane,bis(p-toluenesulfonyl)diazomethane,methansulfonyl-p-toluenesulfonyldiazomethane,cyclohexanesulfonyl-1,1-dimethylethylsulfonyldiazomethane,bis(1,1-dimethylethanesulfonyl)diazomethane,bis(3,3-dimethyl-1,5-dioxaspiro[5.5]dodecane-8-sulfonyl)diazomethane,bis(1,4-dioxaspiro[4.5]decane-7-sulfonyl)diazomethane,bis(t-butylsulfonyl)diazomethane, and the like can be given.

Preferable examples of the above acid generators are as follows.

It is preferable to use at least one compound selected from a groupconsisting of bis(4-t-butylphenyl)iodonium trifluoromethanesulfonate,bis(4-t-butylphenyl)iodonium perfluoro-n-butanesulfonate,bis(4-t-butylphenyl)iodonium p-toluenesulfonate,bis(4-t-butylphenyl)iodonium 10-camphorsulfonate,bis(4-t-butylphenyl)iodonium 2-trifluoromethylbenzenesulfonate,bis(4-t-butylphenyl)iodonium 4-trifluoromethylbenzenesulfonate,bis(4-t-butylphenyl)iodonium 2,4-difluorobenzenesulfonate,triphenylsulfonium trifluoromethanesulfonate, triphenylsulfoniumperfluoro-n-butanesulfonate, triphenylsulfonium p-toluenesulfonate,triphenylsulfonium 10-camphorsulfonate, triphenylsulfonium2-trifluoromethylbenzenesulfonate, triphenylsulfonium4-trifluoromethylbenzenesulfonate, torphenylsulfonium2,4-difluoromethylbenzenesulfonate,N-(trifluoromethanesulfonyloxy)succineimide,N-(trifluoromethanesulfonyloxy)bicycle[2.2.1]hept-5-ene-2,3-dicarboxylmide,N-(10-camphorsulfonyloxy)succineimide,N-(camphorsulfonyloxy)bicyclo[2.2.1]hept-5-ene-dicarboxylmide,N-{(5-methyl-5-carboxymethanebicyclo[2,2,1]hept-2-yl)sulfonyloxy}succinimide,bis(4-t-butylphenyl)iodoniumperfluorooctanesulfonate, diphenyliodoniumnonafluorobutanesulfonate, diphenyliodonium trifluoromethanesulfonate,diphenyliodonium perfluorooctanesulfonate, diphenyliodonium10-coaphorsulfonate, triphenylsulfonium perfluorooctanesulfonate,tri(p-methoxyphenyl)sulfonium trifluoromethanesulfonate,tri(p-methoxyphenyl)sulfonium 10-camphorsulfonate,bis(p-fluorophenyl)iodonium trifluoromethanesulfonate,bis(p-fluorophenyl)iodonium nonafluoromethanesulfonate,bis(p-fluorophenyl)iodonium camphorsulfonate,(p-fluorophenyl)(phenyl)iodonium trifluoromethanesulfonate,tris(p-fluorophenyl)sulfonium trifluoromethanesulfonate,tris(p-fluorophenyl)sulfonium p-toluenesulfonate,(p-fluorophenyl)diphenylsulfonium trifluoromethanesulfonate,N-{(5-methyl-5-carboxymethanebicyclo[2,2,1]hept-2-yl)sulfonyloxy}succinimide,N-(nonafluorobutylsulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxyimide,N-(p-toluenesulfonyloxy)succinimide,N-(benzenesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylmide,bis(cyclohexanesulfonyl)diazomethane,bis(3,3-dimethyl-1,5-dioxaspiro[5.5]dodecane-8-sulfonyl)diazomethane,bis(1,4-dioxaspiro[4.5]decane-7-sulfonyl)diazomethane,bis(t-butylsulfonyl)diazomethane,1-(4-n-butoxynaphthyl)tetrahydrothiopheniumnonafluoro-n-butanesulfonate, triphenylsulfonium1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodecan-8-yl)ethanesulfonate,triphenylsulfonium1,1-difluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodecan-8-yl)ethanesulfonate,1-(4-n-buthoxynaphthyl)tetrahydrothiophenium1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodecan-8-yl)ethanesulfonate,and 1-(4-n-buthoxynaphthyl)tetrahydrothiophenium1,1-difluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodecan-8-yl)ethanesulfonate.

As examples of the acids, carboxylic acids and sulfonic acids can begiven.

Examples of the carboxylic acids and sulfonic acids are as follows.

Examples of the low molecular compounds such as carboxylic acids andsulfonic acids include:

formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid,hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoicacid, undecanoic acid, lauryl acid, tridecane acid, myristic acid,pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid,2-methylpropanoic acid, 2-ethylbutanoic acid, 2-methylbutanoic acid,3-methylbutanoic acid, 2,2-dimethylbutanoic acid, tert-butylacetic acid,(±)-2-methylpentanoic acid, 2-propylpentanoic acid, 3-methylpentanoicacid, 4-methylpentanoic acid, 2-methylhexanoic acid, (±)-2-ethylhexanoicacid, 2-methylheptanoic acid, 4-methyloctanoic acid, oxalic acid,malonic acid, methylmalonic acid, ethylmalonic acid, butylmalonic acid,dimethylmalonic acid, succinic acid, methylbutanedioic acid,2,2-dimethylbutanedioic acid, 2-ethyl-2-methylbutanedioic acid,2,3-dimethylbutanedioic acid, glutaric acid, 2-methylglutaric acid,3-methylglutaric acid, 2,3-dimethylglutaric acid, 2,4-dimethylglutaricacid, 3,3-dimethylglutaric acid, adipic acid, 3-methyladipic acid,2,2,5,5-tetramethyladipic acid, pimelic acid, suberic acid, azelaicacid, sebacic acid, 1,11-undecanedicarboxylic acid, undecanedioic acid,1,12-dodecanedicarboxylic acid, hexadecanedioic acid,1,2,3-propanetricarboxylic acid, 2-methyl-1,2,3-propanetricarboxylicacid, 1,2,3,4-butanetetracarboxylic acid, difluoroacetic acid,trifluoroacetic acid, pentafluoropropanoic acid, heptafluorobutanoicacid, hexafluoroglutaric acid, glycolic acid, 2-hydroxyisobutanoic acid,2-hydroxy-2-methylbutanoic acid, 2-ethyl-2-hydroxybutanoic acid,(±)-2-hydroxy-3-methylbutanoic acid, (±)-2-hydroxy-4-methylpentanoicacid, (±)-2-hydroxyhexanoic acid, 10-hydroxydecanoic acid,12-hydroxydodecanoic acid, 12-hydroxystearic acid, D-marinic acid,(R)-(−)-citramarinic acid, (±)-2-isopropylmarinic acid,3-hydroxy-3-methylglutaric acid, D-tartaric acid, L-tartaric acid,citric acid, (1R,3R,4R,5R)-(−)-quinic acid, methoxyacetic acid,ethoxyacetic acid, 3-methoxypropionic acid, (−)-menthoxyacetic acid,(±)-tetrahydro-2-fronic acid, (±)-tetrahydro-3-fronic acid, thiolaceticacid, thiopivalic acid, 2-mercaptopropionic acid, 3-mercaptopropionicacid, mercaptobutanedioic acid, (methylthio)acetatic acid,thiodiglycolic acid, 3,3′-dithiodipropionic acid,3-carboxypropyldisulfuric acid, (±)-2-(carboxymethylthio)butanedioicacid, 2,2′,2″,2″′-[1,2-ethanediylidenetetrakis(thio)]tetrakisaceticacid, (±)-3-methyl 2-oxopentanoic acid, 5-oxohexanoic acid,6-oxoheptanoic acid, 4,6-dioxoheptanoic acid, 2-oxopentanedionic acid,2-oxohexanedionic acid, 2-oxoheptanedionic acid, 2-oxononanedionic acid,cis-pinoic acid, cyclobutanecarboxylic acid, cyclopentanecarboxylicacid, cyclopentylacetic acid, 3-cyclopentylpropionic acid,cyclohexylacetic acid, dicyclohexylacetic acid, cyclohexanepropionicacid, cyclohexanebutanoic acid, cyclohexanepentanoic acid,1-methyl-1-cyclohexanecarboxylic acid,(±)-2-methyl-1-cyclohexanecarboxylic acid,(±)-3-methyl-1-cyclohexanecarboxylic acid,4-methyl-cyclohexanecarboxylic acid, 4-tert-butylcyclohexanecarboxylicacid, trans-4-pentylcyclohexanecarboxylic acid,4-methyl-cyclohexaneacetic acid, (R)-(−)-hexahydromandelic acid,(S)-(+)-hexahydromandelic acid, 3-methoxycyclohexanecarboxylic acid,4-methoxycyclohexanecarboxylic acid, cycloheptanecarboxylic acid,2-norbornaneacetatic acid,[1R-(2-endo,3-exo)]-3-hydroxy-4,7,7-trimethylbicyclo[2.2.1]heptane-2-aceticacid, (+)-camphorcarboxylic acid, (−)-camphorcarboxylic acid,cis-bicyclo[3.3.0]octane-2-carboxylic acid,anti-3-oxotricyclo[2.2.1.0^(2,6)]heptane-7-carboxylic acid,3-adamantanecarboxylic acid, 1-adamantanecarboxylic acid,1-adamantaneacetic acid, 3-methyl-1-adamantaneacetic acid,trans-DL-1,2-cyclopentanedicarboxylic acid, 1,1-cyclopentanediaceticacid, (1S,3R)-(−)-camphoric acid, 1,1-cyclohexanediacetatic acid,(±)-trans-1,2-cyclohexanedicarboxylic acid,(±)-1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid,1,3-adamantanedicarboxylic acid, 1,3,5-cyclohexanetricarboxylic acid,(1α,3α,5α)-1,3,5-trimethyl-1,3,5-cyclohexanetricarboxylic acid,(1α,3α,5β)-1,3,5-trimethyl-1,3,5-cyclohexanetricarboxylic acid,1,2,3,4-cyclobutanetetracarboxylic acid,cis,cis,cis,cis-1,2,3,4-cyclopentanetetracarboxylic acid,1,2,3,4,5,6-cyclohexanehexacarboxylic acid, benzoic acid, phenylaceticacid, 1-phenyl-1-cyclopentanecarboxylic acid, α-cyclohexylphenylaceticacid, diphenylacetic acid, triphenylacetatic acid, 2-phenylpropionicacid, 3-phenylpropionic acid, 2-benzyl3,3-dimethylbutanoic acid,2,2-diphenylpropionic acid, 3,3-diphenylpropionic acid,3,3,3-triphenylpropionic acid, 2-phenylbutanoic acid,2-ethyl-2-phenylbutanoic acid, 3-phenylbutanoic acid, 4-phenylbutanoicacid, 5-phenylpentanoic acid, 3-methyl-2-phenylpentanoic acid,6-phenylhexanoic acid, α-fluorophenylacetic acid,(R)-(−)-α-methoxyphenylacetic acid, phenoxyacetic acid,3-phenoxypropionic acid, (±)-2-phenoxypropionic acid,11-phenoxyundecanoic acid, 2-phenoxybutanoic acid, (±)-mandelic acid,(±)-α-methoxyphenylacetic acid, 2-hydroxy-3-phenylpropionic acid,tropinic acid, thiophenoxyacetic acid, S-benzylthioglycolic acid,2-ethylthio-2,2-diphenylacetic acid, benzoylformic acid, phenylpyruvicacid, 3-benzoylpropionic acid, 4-benzoylbutanoic acid, phenylmalonicacid, benzylmalonic acid, phenylbutanedioic acid, 3-phenylpentanedioicacid, o-tolylacetic acid, 1,2-phenylenediacetic acid,(±)-1-benzcyclobutenecarboxylic acid, 1,2,3,4-tetrahydro-2-naphthoicacid, (α,α,α-trifluoro-o-tolyl)acetic acid, 2-fluorophenylacetic acid,2-chlorophenylacetic acid, 2-bromophenylacetic acid,(±)-2-(2-chlorophenoxy)propionic acid, 2-methoxyphenylacetic acid,(±)-2-methoxymandelic acid, 3-(2-methoxyphenyl)propionic acid,1,2-phenyleneoxydiacetic acid, 2-hydroxyphenylacetic acid,2-nitrophenylacetic acid, 3-(2-nitrophenyl)-2-oxopropanoic acid,2-formylphenoxyacetic acid, homophthalic acid, m-tolylacetic acid,(α,α,α-trifluoro-m-tolyl)acetic acid, 3-hydroxyphenylacetic acid,3-methoxyphenylacetic acid, 3-methoxymandelic acid, 3-nitrophenylaceticacid, p-tolylacetic acid, (4-methylphenoxy)acetic acid,3-fluorophenylacetic acid, 4-isobutyl-α-methylphenyl acetic acid,4-(4-chloro-o-tolyloxy)butanoic acid, 1,4-phenylenediacetic acid,4-fluorophenylacetic acid, (α,α,α-trifluoro-p-tolyl)acetic acid,4-(trifluoromethyl)mandelic acid, 3-(4-fluorobenzoyl)propionic acid,4-chlorophenylacetic acid, 4-bromophenylacetic acid,3,3,3-tris(4-chlorophenyl)propionic acid, 4-(bromomethyl)phenylaceticacid, 1-(4-chlorophenyl)-1-cyclopentanecarboxylic acid,3-(4-chlorobenzoyl)propionic acid,1-(4-methoxyphenyl)cyclopentanecarboxylic acid,1-(4-methoxyphenyl)cyclohexanecarboxylic acid, 4-methoxyphenylaceticacid, 4-ethoxyphenylacetic acid, 3-(4-methoxyphenyl)propionic acid,4-(4-methoxyphenyl)butanoic acid, 4-hydroxyphenylacetic acid,2-(4-hydroxyphenoxy)propionic acid, 3-(4-hydroxyphenyl)propionic acid,(±)-4-methoxymandelic acid, 4-chlorophenoxyacetic acid,bis(4-chlorophenoxy)acetic acid, 4,4-bis(4-hydroxyphenyl)pentanoic acid,4-bromomandelic acid, 4-(dimethylamino)phenylacetic acid,4-nitrophenylacetic acid, 2-(4-nitrophenyl)propionic acid,4-(4-nitrophenyl)butanoic acid, 3-(4-methoxybenzoyl)propionic acid,4-hydroxyphenylpyruvic acid, D-3-phenyllacetic acid,4-fluorophenoxyacetic acid, (±)-2-(4-chlorophenoxy)propionic acid,2-(4-chlorophenoxy)-2-methylpropionic acid,9,10-dihydro-2-phenanthrenebutanoic acid,9,10-dihydro-γ-oxo-2-phenanthrenebutanoic acid,(2,4-di-tert-pentylphenoxy)acetic acid, 2,6-difluorophenylacetic acid,2,4-difluorophenylacetic acid, 2,5-difluorophenylacetic acid,3,4-difluorophenylacetic acid, 3,5-difluorophenylacetic acid,4-chloro-o-tolyloxyacetic acid, 3,5-bis(trifluoromethyl)phenylaceticacid, (3,4-dimethoxyphenyl)acetic acid, 3,4-(methylenedioxy)phenylaceticacid, 3-fluoro-4-hydroxyphenylacetic acid, 5-methoxy-1-indanone-3-aceticacid, 3-(3,4-dimethoxyphenyl)propionic acid,4-(3,4-dimethoxyphenyl)butanoic acid, (2,5-dimethoxyphenyl)acetic acid,(4-hydroxy-3-methoxyphenyl)acetic acid, (±)-4-hydroxy-3-methoxymandelicacid, (±)-3-hydroxy-4-methoxymandelic acid, DL-3,4-dihydroxymandelicacid, 2,5-dihydroxyphenylacetic acid, 3,4-dihydroxyphenylacetic acid,3,4-dihydroxyhydrocinnamic acid, 4-hydroxy-3-nitrophenylacetic acid,podocarpic acid, 2,5-dihydroxy-1,4-benzenediacetic acid,3,4,5-trimethoxyphenylacetic acid, 3-(3,4,5-trimethoxyphenyl)propionicacid, 2,3,4,5,6-pentafluorophenylacetic acid, 4-biphenylacetic acid,1-naphthylacetic acid, 2-naphthylacetic acid,(±)-α-trityl-2-naphthalenepropionic acid, (1-naphthoxy)acetic acid,(2-naphthoxy)acetic acid, (+)-6-methoxy-α-methyl-2-naphthaleneaceticacid, 9-fluoreneacetic acid, 2-methylbenzoic acid, 2-fluorobenzoic acid,2-trifluoromethylbenzoic acid, 2-methoxybenzoic acid, 2-ethoxybenzoicacid, salicylic acid, thiosalicylic acid, 2-nitrobenzoic acid,2-(p-toluoyl)benzoic acid, 3-methylbenzoic acid, 3-fluorobenzoic acid,3-trifluoromethylbenzoic acid, 3-methoxybenzoic acid, 3-hydroxybenzoicacid, 3-dimethylaminobenzoic acid, 3-nitrobenzoic acid, 4-methylbenzoicacid, 4-ethylbenzoic acid, 4-propylbenzoic acid, 4-isopropylbenzoicacid, 4-butylbenzoic acid, 4-tert-butylbenzoic acid, 4-pentylbenzoicacid, 4-hexylbenzoic acid, 4-heptylbenzoic acid, 4-octylbenzoic acid,4-fluorobenzoic acid, 4-trifluoromethylbenzoic acid,4,4′-(hexafluoroisopropylidene)bis(benzoic acid), 4,4′-oxybis(benzoicacid), 4-methoxybenzoic acid, 4-(trifluoromethoxy)benzoic acid,4-ethoxybenzoic acid, 4-propoxybenzoic acid, 4-pentyloxybenzoic acid,4-hexyloxybenzoic acid, 4-heptyloxbenzoic acid, 4-octyloxbenzoic acid,4-nonyloxybenzoic acid, 4-decyloxybenzoic acid, 4-undecyloxybenzoicacid, 4-dodecyloxybenzoic acid, 4-iso-propoxybenzoic acid,4-hydroxybenzoic acid, 4-(methylthio)benzoic acid, 4-(ethylthio)benzoicacid, 4-dimethylaminobenzoic acid, 4-(diethylamino)benzoic acid,4-nitrobenzoic acid, 4-acetylbenzoic acid, 4-carboxybenzaldehyde,phthalic acid, isophthalic acid, 1,2,3-benzenetricarboxylic acid,terephthalic acid, 1,2,4-benzenetricarboxylic acid,1,3,5-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid,benzenehexacarboxylic acid, 2,3-dimethylbenzoic acid,2,6-dimethylbenzoic acid, 3-fluoro-2-methylbenzoic acid,2,3-difluorobenzoic acid, 2,6-difluorobenzoic acid,2-fluoro-6-trifluoromethylbenzoic acid,2-fluoro-3-trifluoromethylbenzoic acid, 2,6-bis(trifluoromethyl)benzoicacid, 2,3-dimethoxybenzoic acid, 2,6-dimethoxybenzoic acid,3-methylsalicylic acid, 3-isopropylsalicylic acid, 3-methoxysalicylicacid, 3-hydroxysalicylic acid, 6-hydroxysalicylic acid,2-methyl-6-nitrobenzoic acid, 3-methyl-2-nitrobenzoic acid,2-methyl-3-nitrobenzoic acid, 3-methoxy-2-nitrobenzoic acid,3-nitrophthalic acid, 2,4-dimethylbenzoic acid, 2,5-dimethylbenzoicacid, 5-fluoro-2-methylbenzoic acid, 3-fluoro-4-methylbenzoic acid,2,4-bis(trifluoromethyl)benzoic acid, 2,5-bis(trifluoromethyl)benzoicacid, 2,4-difluorobenzoic acid, 3,4-difluorobenzoic acid,2-fluoro-4-trifluoromethylbenzoic acid, 2,5-difluorobenzoic acid,3-methoxy-4-methylbenzoic acid, 3-fluoro-4-methoxybenzoic acid,2,4-dimethoxybenzoic acid, 2,5-dimethoxybenzoic acid,3,4-dimethoxybenzoic acid, 3,4-diethoxybenzoic acid, piperonylic acid,3-hydroxy-4-methylbenzoic acid, 4-methylsalicylic acid,5-methylsalicylic acid, 5-fluorosalicylic acid,2-methoxy-4-(methylthio)benzoic acid, 5-methoxysalicylic acid,4-methoxysalicylic acid, 4-hydroxy-3-methoxybenzoic acid,3-hydroxy-4-methoxybenzoic acid, 3,4-dihydroxybenzoic acid,2,5-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid,4-diethylaminosalicylic acid, 5-methyl-2-nitrobenzoic acid,4-methyl-3-nitrobenzoic acid, 3-methyl-4-nitrobenzoic acid,2-methyl-5-nitrobenzoic acid, 2-fluoro-5-nitrobenzoic acid,4-fluoro-3-nitrobenzoic acid, 4-methoxy-3-nitrobenzoic acid,3-methoxy-4-nitrobenzoic acid, 3-hydroxy-4-nitrobenzoic acid,2-hydroxy-5-nitrobenzoic acid, 2,4-dinitrobenzoic acid,3,4-dinitrobenzoic acid, 4-methylphthalic acid, 4-hydroxyisophthalicacid, 4-nitrophthalic acid, nitroterephthalic acid,1,4-pehnylenedipropionic acid, 3,5-dimethylbenzoic acid,3,5-di-tert-butylbenzoic acid, 3,5-difluorobenzoic acid,3,5-bis(trifluoromethyl)benzoic acid, 3,5-dimethoxybenzoic acid,3,5-dihydroxybenzoic acid, 3,5-dinitrobenzoic acid,5-tert-butylisophthalic acid, 5-nitroisophthalic acid,5-(4-carboxy-2-nitrophenoxy)isophthalic acid, 2,3,4-trifluorobenzoicacid, 2,3,6-trifluorobenzoic acid, 2,4,6-trimethylbenzoic acid,2,4,6-trifluorobenzoic acid, 3,4,5-trifluorobenzoic acid,3,4,5-trimethoxybenzoic acid, 3,4,5-triethoxybenzoic acid,2-hydroxy-3-isopropyl-6-methylbenzoic acid,2-hydroxy-6-isopropyl-3-methylbenzoic acid, 3,5-diisopropylsalicylicacid, 3,5-di-tert-butyl-4-hydroxybenzoic acid, 2,3,4-trihydroxybenzoicacid, 3,4,5-trihydroxybenzoic acid, 3-hydroxy-4,5-dimethoxybenzoic acid,4-hydroxy-3,5-dimethoxybenzoic acid, 4,5-dimethoxy-2-nitrobenzoic acid,4-methyl-3,5-dinitrobenzoic acid, 4-hydroxy-3,5-dinitrobenzoic acid,3,5-dinitrosalicylic acid, 3-hydroxy-4-methyl-2-nitrobenzoic acid,2,3,4-trimethoxybenzoic acid, 2,4,5-trifluorobenzoic acid,2,4,5-trimethoxybenzoic acid, 2,5-dihydroxyterephthalic acid,2,3,4,5-tetrafluorobenzoic acid, 2,3,5,6-tetrafluorobenzoic acid,2,3,5,6-tetrafluoro-4-methylbenzoic acid, pentafluorobenzoic acid,tetrafluoroterephthalic acid, tetrafluoroisophthalic acid,tetrafluorophthalic acid, 2-biphenylcarboxylic acid,4′-hydroxy-4-biphenylcarboxylic acid, 4,4′-biphenyldicarboxylic acid,2-benzylbenzoic acid, 2-bibenzylcarboxylic acid,2,3,4,5,6-pentafluorophenoxyacetic acid, 2-phenoxybenzoic acid,3-phenoxybenzoic acid, 4-phenoxybenzoic acid, 2-benzoylbenzoic acid,3-benzoylbenzoic acid, 4-benzoylbenzoic acid, 2-(4-fluorobenzoyl)benzoicacid, 4-[4-(2-carboxybenzoyl)phenyl]butanoic acid,1-naphthalenecarboxylic acid, 2-naphthalenecarboxylic acid,4-fluoro-1-naphthalenecarboxylic acid, 1-hydroxy-2-naphthalenecarboxylicacid, 2-hydroxy-1-naphthalenecarboxylic acid,3-hydroxy-2-naphthalenecarboxylic acid, 2-ethoxy-1-naphthalenecarboxylicacid, 1,4-dihydroxy-2-naphthalenecarboxylic acid,3,5-dihydroxy-2-naphthalenecarboxylic acid, 1,4-naphthalenedicarboxylicacid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylicacid, 1-(8-carboxy)naphthaldehyde, 2-biphenylenecarboxylic acid,9-fluorenecarboxylic acid, 1-fluorenecarboxylic acid,4-fluorenecarboxylic acid, 9-hydroxy-1-fluorenecarboxylic acid,9-hydroxy-9-fluorenecarboxylic acid, 9-fluorene-1-carboxylic acid,9-fluorene-2-carboxylic acid, 9-fluorene-4-carboxylic acid,7-nitro-9-oxo-4-fluorenecarboxylic acid, 9-anthracenecarboxylic acid,9,10-anthracenedipropionic acid, xanthene-9-carboxylic acid,2,7-di-tert-butyl-9,9-dimethyl-4,5-xanthenedicarboxylic acid,2,2′-(ethylenedioxy)dianiline-N,N,N′,N′-tetraacetic acid,N-carbobenzyloxy-2-methylalanine, N-(4-nitrobenzoyl)-β-alanine,N-acetyl-2-fluoro-DL-phenylalanine, N-acetyl-3-fluoro-DL-phenylalanine,N-acetyl-4-fluoro-DL-phenylalanine, methanesulfonic acid, ethanesulfonicacid, taurine,3-[(1,1-dimethyl-2-hydroxyethyl)amino]-2-hydroxy-1-propanesulfonic acid,3-[bis(2-hydroxyethyl)amino]-2-hydroxy-1-propanesulfonic acid,(1R)-(−)-10-camphorsulfonic acid, (1S)-(+)-10-camphorsulfonic acid,trifluoromethylsulfonic acid, perfluorobutanesulfonic acid,perfluorooctanesulfonic acid, (methylamino)sulfonic acid,(butylamino)sulfonic acid,1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodecan-8-yl)ethanesulfonicacid, and1,1-difluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodecan-8-yl)ethanesulfonicacid.

Preferable acids among the above carboxylic acids and sulfonic acids aregiven below.

Acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoicacid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid,undecanoic acid, lauryicl acid, tridecanic acid, myristic acid,pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid,2-methylpropane acid, 2-ethylbutanoic acid, 2-methylbutanoic acid,3-methylbutanoic acid, 2,2-dimethylbutanoic acid, tert-butylacetic acid,(±)-2-methylpentanoic acid, 2-propylpentanoic acid, 3-methylpentanoicacid, 4-methylpentanoic acid, 2-methylhexanoic acid, (±)-2-ethylhexanoicacid, 2-methylheptanoic acid, 4-methyloctanoic acid, oxalic acid,malonic acid, methylmalonic acid, ethylmalonic acid, butylmalonic acid,dimethylmalonic acid, succinic acid, methylbutanedioic acid,2,2-dimethylbutanedioic acid, 2-ethyl-2-methylbutanedioic acid,2,3-dimethylbutanedioic acid, glutaric acid, 2-methylglutaric acid,3-methylglutaric acid, 2,3-dimethylglutaric acid, 2,4-dimethylglutaricacid, 3,3-dimethylglutaric acid, adipic acid, 3-methyladipic acid,2,2,5,5-tetramethyladipic acid, pimelic acid, suberic acid, azelaicacid, sebacic acid, 1,11-undecanedicarboxylic acid, undecanedioic acid,1,12-dodecanedicarboxylic acid, hexadecanedioic acid,1,2,3-propanetricarboxylic acid, 2-methyl-1,2,3-propanetricarboxylicacid, 1,2,3,4-butanetetracarboxylic acid, difluoroacetic acid,trifluoroacetic acid, pentafluoropropanoic acid, heptafluorobutanoicacid, hexafluoroglutaric acid, 10-hydroxydecanoic acid,12-hydroxydodecanoic acid, 12-hydroxystearic acid, citric acid,(−)-menthoxyacetic acid, thiolacetic acid, thiopivalic acid,(methylthio)acetic acid, thiodiglycolic acid,(±)-2-(carboxymethylthio)butanedioic acid,2,2′,2″,2″′-[1,2-ethanediylidenetetrakis(thio)]tetrakisacetic acid,(±)-3-methyl-2-oxopentanoic acid, 5-oxohexanoic acid, 6-oxoheptanoicacid, 2-oxopentanedioic acid, 2-oxohexanedioic acid, 4-oxoheptanedioicacid, 5-oxononanedioic acid, cyclopentanecarboxylic acid,cyclopentylacetic acid, 3-cyclopentylpropionic acid, cyclohexylaceticacid, dicyclohexylacetic acid, cyclohexanepropionic acid,cyclohexanebutanoic acid, cyclohexanepentanoic acid,(±)-2-methyl-1-cyclohexanecarboxylic acid,(±)-3-methyl-1-cyclohexanecarboxylic acid,4-methyl-cyclohexanecarboxylic acid, 4-tert-butylcyclohexane carboxylicacid, trans-4-pentylcyclohexane carboxylic acid,4-methylcyclohexanacetic acid, 3-methoxycyclohexanecarboxylic acid,4-methoxycyclohexanecarboxylic acid, cycloheptanecarboxylic acid,2-norbornaneacetic acid,[1R-(2-endo,3-exo)]-3-hydroxy-4,7,7-trimethylbicyclo[2.2.1]heptane-2-aceticacid, (+)-camphorcarboxylic acid, (−)-camphorcarboxylic acid,cis-bicyclo[3.3.0]octane-2-carboxylic acid,anti-3-oxotricyclo[2.2.1.0^(2,6)]heptane-7-carboxylic acid,3-adamantanecarboxylic acid, 1-adamantanecarboxylic acid, 1-adamantaneacetic acid, 3-methyl1-adamantane acetic acid,trans-DL-1,2-cyclopentanedicarboxylic acid, 1,1-cyclopentanediaceticacid, (1S,3R)-(−)-camphoric acid, (±)-trans-1,2-cyclohexanedicarboxylicacid, (±)-1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylicacid, 1,3-adamantanedicarboxylic acid, 1,3,5-cyclohexanetricarboxylicacid, (1α,3α,5α)-1,3,5-trimethyl-1,3,5-cyclohexanetricarboxylic acid,(1α,3α,5β)-1,3,5-trimethyl-1,3,5-cyclohexanetricarboxylic acid,cis,cis,cis,cis-1,2,3,4-cyclopentanetetracarboxylic acid,1,2,3,4,5,6-cyclohexanehexacarboxylic acid, benzoic acid, phenylaceticacid, 2-phenylpropionic acid, 3-phenylpropionic acid,α-fluorophenylacetic acid, 3-phenoxypropionic acid,(±)-2-phenoxypropionic acid, (±)-α-methoxyphenylacetic acid,o-tolylacetic acid, 1,2-phenylenediacetic acid,1,2,3,4-tetrahydro-2-naphthoic acid, (α,α,α-trifluoro-o-tolyl)aceticacid, 2-fluorophenylacetic acid, 2-methoxyphenylacetic acid,2-nitrophenylacetic acid, 3-(2-nitrophenyl)-2-oxopropanoic acid,(α,α,α-trifluoro-m-tolyl)acetic acid, 3-nitrophenylacetic acid,3-fluorophenylacetic acid, 4-fluorophenylacetic acid,(α,α,α-trifluoro-p-tolyl)acetic acid, 4-nitrophenylacetic acid,4-fluorophenoxyacetic acid, 2,6-difluorophenylacetic acid,2,4-difluorophenylacetic acid, 2,5-difluorophenylacetic acid,3,4-difluorophenylacetic acid, 3,5-difluorophenylacetic acid,3,5-bis(trifluoromethyl)phenylacetic acid,3-fluoro-4-hydroxyphenylacetic acid, (2,5-dimethoxyphenyl)acetic acid,4-hydroxy-3-nitrophenylacetic acid, 2,3,4,5,6-pentafluorophenylaceticacid, 1-naphthylacetic acid, 2-naphthylacetic acid, (1-naphthoxy)aceticacid, (2-naphthoxy)acetic acid, 2-fluorobenzoic acid,2-trifluoromethylbenzoic acid, 2-nitrobenzoic acid, 3-fluorobenzoicacid, 3-trifluoromethylbenzoic acid, 3-methoxybenzoic acid,4-fluorobenzoic acid, 4-trifluoromethylbenzoic acid, 4-nitrobenzoicacid, 3-fluoro-2-methylbenzoic acid, 2,3-difluorobenzoic acid,2,6-difluorobenzoic acid, 2-fluoro-6-trifluoromethylbenzoic acid,2-fluoro-3-trifluoromethylbenzoic acid, 2,6-bis(trifluoromethyl)benzoicacid, 2-methyl-6-nitrobenzoic acid, 3-methyl-2-nitrobenzoic acid,2-methyl-3-nitrobenzoic acid, 5-fluoro-2-methylbenzoic acid,3-fluoro-4-methylbenzoic acid, 2,4-bis(trifluoromethyl)benzoic acid,2,5-bis(trifluoromethyl)benzoic acid, 2,4-difluorobenzoic acid,3,4-difluorobenzoic acid, 2-fluoro-4-trifluoromethylbenzoic acid,2,5-difluorobenzoic acid, 3-fluoro-4-methoxybenzoic acid,5-methyl-2-nitrobenzoic acid, 4-methyl-3-nitrobenzoic acid,3-methyl-4-nitrobenzoic acid, 2-methyl-5-nitrobenzoic acid,2-fluoro-5-nitrobenzoic acid, 4-fluoro-3-nitrobenzoic acid,4-methoxy-3-nitrobenzoic acid, 3-methoxy-4-nitrobenzoic acid,3-hydroxy-4-nitrobenzoic acid, 2-hydroxy-5-nitrobenzoic acid,2,4-dinitrobenzoic acid, 3,4-dinitrobenzoic acid, 3,5-difluorobenzoicacid, 3,5-bis(trifluoromethyl)benzoic acid, 3,5-dinitrobenzoic acid,2,3,4-trifluorobenzoic acid, 2,3,6-trifluorobenzoic acid,2,4,6-trifluorobenzoic acid, 3,4,5-trifluorobenzoic acid,4-methyl-3,5-dinitrobenzoic acid, 4-hydroxy-3,5-dinitrobenzoic acid,3,5-dinitrosalicylic acid, 2,4,5-trifluorobenzoic acid,2,34,5-tetrafluorobenzoic acid, 2,3,5,6-tetrafluorobenzoic acid,2,3,5,6-tetrafluoro-4-methylbenzoic acid, pentafluorobenzoic acid,2,3,4,5,6-pentafluorophenoxyacetic acid, 1-naphthalenecarboxylic acid,2-naphthalenecarboxylic acid, 4-fluoro-1-naphthalenecarboxylic acid,1-hydroxy-2-naphthalenecarboxylic acid,2-hydroxy-1-naphthalenecarboxylic acid,3-hydroxy-2-naphthalenecarboxylic acid,1,4-dihydroxy-2-naphthalenecarboxylic acid,3,5-dihydroxy-2-naphthalenecarboxylic acid, 1,4-naphthalenedicarboxylicacid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylicacid, methanesulfonic acid, ethanesulfonic acid, taurine,3-[(1,1-dimethyl-2-hydroxyethyl)amino]-2-hydroxy-1-propanesulfonic acid,3-[bis(2-hydroxyethyl)amino]-2-hydroxy-1-propanesulfonic acid,(1R)-(−)-10-camphorsulfonic acid, (1S)-(+)-10-camphorsulfonic acid,trifluoromethylsulfonic acid, perfluorobutanesulfonic acid,perfluorooctanesulfonic acid, (methylamino)sulfonic acid,(butylamino)sulfonic acid,1,1,2,2-tetrafluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodecan-8-yl)ethanesulfonicacid, and1,1-difluoro-2-(tetracyclo[4.4.0.1^(2,5).1^(7,10)]dodecan-8-yl)ethanesulfonic acid. At least one acid selected from these acids is preferablyused.

These acid generators and acids may be used either individually or incombination of two or more.

The amount of the acid generator or the acid to be added is usually 10parts by weight or less, preferably 0.001 to 5 parts by weigh, and stillmore preferably 0.005 to 3 parts by weight for 100 parts by weight ofthe resin. If the amount of the acid generator or the acid exceeds 10parts by weight, there is a tendency that the lens of a projectionaligner is polluted by the component eluted from the upper layer-formingcomposition.

In addition, an acid diffusion controller may be added to the upperlayer-forming composition for immersion lithography of the embodiment inorder to increase lithography performance of the resist.

As examples of such acid diffusion controllers, a compound shown by thefollowing formula (10) (hereinafter called “nitrogen-containing compound(I)”), diamino compounds having two nitrogen atoms in a molecule(hereinafter referred to as “nitrogen-containing compound (II)”),diamino polymers having three or more nitrogen atoms in a molecule(hereinafter referred to as “nitrogen-containing compounds (III)”),amide group-containing compounds, urea compounds, and othernitrogen-containing heterocyclic compounds can be given.

wherein R¹⁵s, which may be either the same or different, represent ahydrogen atom, an alkyl group, an aryl group, or an aralkyl group(including the groups in which the hydrogen atom in the alkyl group, thearyl group, or the aralkyl group is replaced by a functional group suchas a hydroxyl group, for example).

As examples of the nitrogen-containing compound (I), monoalkylaminessuch as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, andn-decylamine; dialkylamines such as di-n-butylamine, di-n-pentylamine,di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, anddi-n-decylamine; trialkylamines such as triethylamine,tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine,tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine,and tri-n-decylamine; aromatic amines such as aniline, N-methylaniline,N,N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline,4-nitroaniline, diphenylamine, triphenylamine, and 1-naphthylamine canbe given.

As examples of the nitrogen-containing compound (II), ethylenediamine,N,N,N′,N′-tetramethylethylenediamine,N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine,tetramethylenediamine, hexamethylenediamine,4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether,4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine,2,2′-bis(4-aminophenyl)propane,2-(3-aminophenyl)-2-(4-aminophenyl)propane,2-(4-aminophenyl)-2-(3-hydroxyphenyl)propane,2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane,1,4-bis[1-(4-aminophenyl)-1-methylethyl]benzene,1,3-bis[1-(4-aminophenyl)-1-methylethyl]benzene, and the like can begiven.

As examples of the nitrogen-containing compound (III),polyethyleneimine, polyallylamine, a polymer ofdimethylaminoethylacrylamide, and the like can be given.

As examples of the amide group-containing compound, formamide,N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide,N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone,N-methylpyrrolidone, and the like can be given.

Examples of the urea compound include urea, methylurea,1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea,1,3-diphenylurea, tributylthiourea, and the like.

As examples of the nitrogen-containing heterocyclic compound,imidazoleses such as imidazole, benzimidazole, 4-methylimidazole,4-methyl-2-phenylimidazole, and 2-phenylbenzimidazole; pyridines such aspyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine,4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine,N-methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide,quinoline, 8-oxyquinoline, and acridine; pyrazine, pyrazole, pyridazine,quinoxaline, purine, pyrrolidine, piperidine, morpholine,4-methylmorpholine, piperazine, 1,4-dimethylpiperazine,1,4-diazabicyclo[2.2.2]octane, and the like can be given.

A base precursor having an acid-dissociable group can also be used as anacid diffusion controller. As specific examples,N-(t-butoxycarbonyl)piperidine, N-(t-butoxycarbonyl)imidazole,N-(t-butoxycarbonyl)benzimidazole,N-(t-butoxycarbonyl)-2-phenylbenzimidazole,N-(t-butoxycarbonyl)dioctylamine, N-(t-butoxycarbonyl)diethanolamine,N-(t-butoxycarbonyl)dicyclohexylamine,N-(t-butoxycarbonyl)diphenylamine, and the like can be given.

Of these nitrogen-containing organic compounds, the nitrogen-containingcompound (I) and the nitrogen-containing heterocyclic compound arepreferable. Trialkylamines are particularly preferable among thenitrogen-containing compounds (I), and imidazoles are particularlypreferable among the nitrogen-containing heterocyclic compounds.

The acid diffusion controllers may be used either individually or incombination of two or more.

The amount of the acid diffusion controller to be added is usually 10parts by weight or less, preferably 0.001 to 5 parts by weigh, and morepreferably 0.005 to 3 parts by weight for 100 parts by weight of theresin. If the amount of the acid diffusion controllers exceeds 10 partsby weight, there is a tendency that the lens of a projection aligner ispolluted by the component eluted from the upper layer-formingcomposition.

The photoresist patterning method of the embodiment of the presentinvention will be described below.

As the substrate on which the photoresist film is formed by applying thephotoresist composition, a silicon wafer, an aluminum-coated wafer, orthe like may be used. In order to bring out the potential of the resistfilm to the maximum extent, an organic or inorganic antireflection filmmay be formed on the substrate as disclosed in JP-B-6-12452, forexample.

The photoresist used is not particularly limited, and may beappropriately selected according to the purpose of the resist. Asexamples of the resist, a chemically-amplified positive-tone ornegative-tone resist containing an acid generator can be given.

When the upper layer film produced from the composition of theembodiment is used, a positive-tone resist is particularly preferable.In the case of the chemically-amplified positive-tone resist, theacid-dissociating organic group in the polymer dissociates due to theaction of the acid generated from the acid generator by exposure toradiation, to produce a carboxyl group, for example. The acid increasesthe solubility of the resist in the irradiated part in an alkalinedeveloper to the extent that the irradiated part is dissolved andremoved by an alkaline developer to produce a positive tone resistpattern.

The photoresist film can be obtained by dissolving the resin for formingthe photoresist film in a suitable solvent at a solid componentconcentration of 0.1 to 20 wt %, for example, filtering the solutionthrough a filter with a pore size of about 30 nm, for example, to obtaina resist solution, applying the resist solution on a substrate by anappropriate method such as rotation application, cast coating, or rollcoating, and preliminarily baking (hereinafter referred to as “PB”) thecoated resin composition to vaporize the solvent. In this case, acommercially available resist solution may be used as is.

The step of forming an upper layer film on the photoresist film usingthe upper layer-forming composition comprises applying the upperlayer-forming composition of the embodiment on the photoresist film and,usually, again baking the coating to obtain the upper layer film of theembodiment. This step is carried out in order to protect the photoresistfilm and to prevent pollution of the lens of a projection aligner due toelution of components from the photoresist film into the liquid used forthe immersion lithography.

In this instance, the closer the thickness of the upper layer film to ananisoploid of λ/4 m (wherein λ is the wavelength of radiation and m isthe refractive index of the upper layer film), the greater theantireflection effect on the upper side surface of the resist film.Therefore, it is preferable to bring the thickness of the upper layerfilm close to this value. In the embodiment, either prebaking after theapplication of the resist solution or baking after the application ofthe upper layer film forming-composition solution may be omitted forsimplification of the process.

A step of forming a resist pattern by irradiating the photoresist filmand the upper layer film with light in water as a medium through a maskhaving a specified pattern and developing the pattern, comprises a stepof carrying out liquid immersion lithography and, after baking at aspecified temperature, developing the pattern.

It is possible to adjust the pH of water filled between the photoresistfilm and the upper layer film. A particularly preferable liquid mediumis pure water.

As the radiation used for the liquid immersion lithography, variousradiations such as visible rays; ultraviolet rays such as a g-line andi-line; deep ultraviolet rays such as an excimer laser; X rays such as asynchrotron radiation line; and charged particle beams such as anelectron beams can be selectively used according to the photoresist filmand the combination of the photoresist film and the upper layer film foruse in immersion lithography. In particular, it is preferable to uselight from an ArF excimer laser (wavelength: 193 nm) or a KrF excimerlaser (wavelength: 248 nm).

It is preferable to perform post exposure baking (hereinafterabbreviated as “PEB”) in order to provide the resist film with improvedresolution, pattern profile, developability, and the like. The bakingtemperature is usually about 30 to 200° C., and preferably 50 to 150°C., although the baking temperature is appropriately adjusted accordingto the resist used and the like.

The photoresist film is then developed using a developer and washed toform a desired resist pattern. In this case, it is not necessary to adda step of delaminating the upper film for immersion lithography. Theupper film is completely removed during development or washing after thedevelopment. This is an important feature of the embodiment.

As the developer used when forming the resist pattern in the embodiment,an alkaline aqueous solution in which sodium hydroxide, potassiumhydroxide, sodium carbonate, sodium silicate, meta sodium silicate,ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine,triethylamine, methyldiethylamine, dimethylethanolamine,triethanolamine, tetramethylammonium hydroxide, tetraethylammoniumhydroxide, pyrrole, piperidine, choline,1,8-diazabicyclo-[5,4,0]-7-undecene, 1,5-diazabicyclo-[4,3,0]-5-nonane,or the like is dissolved can be used. An appropriate amount of awater-soluble organic solvent such as alcohols including methanol andethanol or a surfactant can be added to the developer. When developedusing these alkaline aqueous solution, the resist film is usually washedwith water after the development.

EXAMPLES

The embodiment of the present invention will be described in more detailby Synthesis Examples of the copolymer (polymer) and Examples of theupper layer-forming composition. However, these examples should not beconstrued as limiting the present invention. In the examples, “part”refers to “part by mass” unless otherwise indicated.

Resin Synthesis Example

Resins (A-1) to (A-10) which can form a film stable in water duringexposure to radiation and is dissolved in a developer after resistpattern formation were synthesized according to the method describedbelow. Mw and Mn of the resins (A-1) to (A-10) were measured by gelpermeation chromatography (GPC) using GPC columns (“G2000H_(XL)”×2,“G3000HX_(XL)”×1, and “G4000H_(XL)”×1, manufactured by Tosoh Corp.) in ahigh performance GPC apparatus (“HLC-8120” manufactured by Tosoh Corp.)under the following conditions; Flow rate: 1.0 ml/minute, eluate:tetrahydrofuran, column temperature: 40° C., standard referencematerial: monodispersed polystyrene.

The radically polymerizable monomers used for the synthesis of theresins are shown in the following formulas (M-1) to (M-6), (S-1), and(S-2).

The monomer solutions were prepared by dissolving monomers of a weightcorresponding to mol % shown in Table 1 and2,2′-azobis(methyl-2-methylpropionate) as an initiator in 200 g ofisopropanol. The total amount of the monomers used for the reaction wasadjusted to 100 g. The amount of the initiator is indicated by gram (g)to 100 g of the monomers.

A 1500 ml three-necked flask equipped with a thermometer and a droppingfunnel was charged with 100 g of isopropanol and purged with nitrogenfor 30 minutes. The contents of the flask were heated to 80° C. whilestirring using a magnetic stirrer. The monomer solution prepared asabove was put into the dropping funnel and added to the flask dropwiseover three hours. After the addition, the mixture was reacted for threehours, and allowed to cool to 30° C. or less, thereby obtaining acopolymer solution.

The resulting copolymer was post-treated according to the followingmethod.

The copolymer solution was condensed to 200 g and transferred to aseparating funnel together with 200 g of methanol and 1600 g ofn-heptane. The mixture was sufficiently stirred and the lower layer wasseparated. The separated lower layer was mixed with 200 g of methanoland 1600 g of n-heptane and the mixture was transferred to a separatingfunnel to separate the lower layer. The solvent in the resulting lowerlayer was replaced with dibutyl ether. For comparison, a resin wasobtained by replacing the solvent with 4-methyl-2-pentanol instead ofthe dibutyl ether. The solid component concentration of the sample ofwhich the solvent was replaced was calculated from the weight of theresidue when 0.3 g of the resin solution placed on an aluminum pan washeated on a hot plate at 140° C. for two hours. The calculated value wasused for preparation of solutions for an upper layer-forming compositionand calculation of the yields in the subsequent experiments. After thesolvent replacement with dibutyl ether, the Mw and Mw/Mn (molecularweight dispersion) of the resin were measured. The results are shown inTable 1. The properties of the resin of which the solvent was replacedwith 4-methyl-2-pentanol were almost the same.

TABLE 1 Amount of monomer used for reaction, mol % Amount of Resin M-1M-2 M-3 M-4 M-5 M-6 S-1 S-2 initiator Mw Mw/Mn A-1 100  — — — — — — —6.5 11800  2.3 A-2 — 100 — — — — — — 6.5 10700  2.1 A-3 95 — — — — —  5— 6.3 6120 1.8 A-4 90 — — — — — 10 — 6.2 6000 1.7 A-5 85 — — — — — 15 —6.0 5830 1.7 A-6 95 — — — — — —  5 6.3 6080 1.7 A-7 90 — — — — — — 106.2 5900 1.7 A-8 85 — — — — — — 15 6.0 5730 1.5 A-9  42.5 — 42.5 — — — —15 6.0 4830 1.5 A-10 — — — 30 40 30 — — 6.0 7300 1.6

Preparation of Radiation-Sensitive Resin Compositions

The radiation-sensitive resin compositions for forming photoresist filmswere prepared using the following method.

Preparation of Radiation-Sensitive Resin (A′)

A monomer solution was prepared by dissolving 53.93 g (50 mol %) ofcompound (1-1), 10.69 g (10 mol %) of compound (1-2), and 35.38 g (40mol %) of compound (1-3) in 195 g of 2-butanone, and further adding 2.24g of dimethyl 2,2′-azobis(2-methylpropionate). A 1000 ml three-neckedflask was charged with 100 g of 2-butanone and nitrogen gas was bubbledinto the flask for 30 minutes. After the nitrogen purge, the flask washeated to 80° C. while stirring and the above monomer solution was addeddropwise using a dropping funnel over three hours. The polymerizationreaction was carried out for six hours after initiation of the additionof the monomer solution. After completion of polymerization, the polymersolution was cooled with water to 30° C. or lower and poured into 2000 gof methanol. A white precipitate produced was collected by filtration.

The white powder collected by filtration was washed twice with 400 g ofmethanol in a slurry state, filtered again, and dried at 50° C. for 17hours to obtain a polymer in the form of a white powder (72 g, yield72%). The polymer was a copolymer with an Mw of 8,500 and the mol %ratio of the recurring units of the compound (1-1), compound (1-2), andcompound (1-3) determined by ¹³C-NMR was 52.2:8.0:39.8 (mol %).

A homogeneous solution was prepared from the copolymer (A′), as a resincomponent, and the other components shown below in proportions shown inTable 2, and filtered through a membrane filter with a pore size of 500nm to obtain the composition solutions of Examples and ComparativeExamples. In the examples, “part” refers to “part by weight” unlessotherwise indicated.

Acid Generator (B)

B-1: triphenylsulfonium nonafluoro-n-butanesulfonateB-2: 1-(4-n-butoxynaphthalen-1-yl)tetrahydrothiopheniumnonafluoro-n-butanesulfonate

Acid Diffusion Controller (C)

C-1: R-(+)-(tert-butoxycarbonyl)-2-piperidinemethanol

Solvent (D)

D-1: □-butyrolactone (GBL)D-2: propylene glycol monoethyl ether acetate (PEGMEA)

TABLE 2 Acid Acid Acid dissociable generator diffusion group-containing(B) controller Solvent (D) resin (A′) (part by (C) (part by (part by(part by weight) weight) weight) weight) Radiation- A′ (100) B-1 (1.5)C-1 (0.52) D-1 (26.5) sensitive B-2 (6) D-2 (1368.5) resin composition

Examples 1 to 30 and 37 to 48 and Comparative Examples 1 to 11

Upper layer-forming compositions for use in immersion lithography wereproduced using the resins obtained in the above examples. 4 g of thesolid component of each of the resins shown in Table 1 in turn and 96 gof a solvent or a mixture of solvents at a ratio shown in Table 4 orTable 5 were mixed and stirred for two hours. The mixture was filteredthrough a filter with a pore size of 200 nm to obtain a solution. InTable 4, DBE stands for dibutyl ether, 4M2P stands for4-methyl-2-pentanol, and DIAE stands for diisoamyl ether. In Tables 4and 5, the solvent ratio for mixed solvents is shown by weight. Theupper layer-forming compositions obtained were evaluated by thefollowing methods. The results are shown in Tables 4 and 5.

Examples 31 to 36

Homogeneous solutions were prepared from the resin A-1 obtained in theabove Synthesis Example as a resin component and the other componentsshown below in the proportion shown in Table 3, and filtered through amembrane filter with a pore size of 500 nm to obtain the upperlayer-forming compositions for use in immersion lithography of theExamples. In the examples, “part”refers to “part by weight” unlessotherwise indicated. The upper layer-forming compositions obtained wereevaluated by the following methods. The results are shown in Table 4.

Acid or Acid Generator (B′)

B′-1: triphenylsulfonium nonafluoro-n-butanesulfonateB′-3: perfluorobutanesulfonic acid

Acid Diffusion Controller (C)

C-1: R-(+)-(tert-butoxycarbonyl)-2-piperidinemethanol

Solvent (D)

D-3: dibutyl ether (DBE)D-4: 4-methyl-2-pentanol (4M2P)

TABLE 3 Acid generator Acid diffusion Resin (A) (B′) controller (C)Solvent (D) Example 31 A-1 (100) B′-1 (0.3) — D-3 (2400) Example 32 A-1(100) B′-1 (0.3) — D-3 (1680) D-4 (720) Example 33 A-1 (100) B′-3 (0.5)— D-3 (2400) Example 34 A-1 (100) B′-3 (0.5) — D-3 (1680) D-4 (720)Example 35 A-1 (100) B′-3 (0.5) C-1 (0.054) D-3 (2400) Example 36 A-1(100) B′-3 (0.5) C-1 (0.054) D-3 (1680) D-4 (720)

Evaluation Method (1) Evaluation Method of Solubility (Solubility)

In Examples 1 to 30, Examples 37 to 48, and Comparative Examples 1 to10, 4 g of the resin for upper layer-forming composition was added to 96g of the solvent shown in Table 4 or Table 5, and the mixture wasstirred for three hours at 100 rpm using a three-one motor. In Examples1 to 30 and Examples 37 to 48, the resin obtained by drying the resinsolution at 100° C. for 24 hours to a solid state was used. In theevaluation, the resin producing a homogeneous mixture with the solventwas evaluated to have good solubility and indicated as “Good”, and theresin producing undissolved matter or exhibiting turbidity was evaluatedto have poor solubility and indicated as “Bad”.

In Examples 31 to 36, in the case in which the upper layer-formingcomposition shown in Table 3 produced a homogeneous solution, thecomposition was evaluated as having good solubility and indicated as“Good”, and in the case in which an undissolved matter or turbidity wasproduced, the composition was evaluated as having poor solubility andindicated as “Bad”.

(2) Evaluation Method of Upper Layer Film Removability (Removability)

The upper layer film-forming compositions were spin-coated on eight-inchsilicon wafers using “CLEAN TRACK ACT8” (manufactured by Tokyo Electron,Ltd.) and baked at 90° C. for 60 seconds to form coatings with athickness of 90 nm. The thickness was measured by using “Lambda AceVM-90” (manufactured by Dainippon Screen Mfg. Co., Ltd.). After paddledevelopment (developer: 2.38% aqueous solution of TMAH) for 60 secondsusing “CLEAN TRACK ACT8”, the wafers were dried by spinning to observethe surfaces. If development was completed with no residues beingobserved, the removability was judged to be “Good”. If a residue wasobserved, the removability was judged to be “Bad”.

(3) Evaluation Method of Intermixing (Intermixing)

A radiation-sensitive resin composition containing the aboveradiation-sensitive resin (A′) as a resin component was spin-coated onan eight-inch silicon wafer treated with HMDS (100° C. for 60 seconds)using “CLEAN TRACK ACT8” (manufactured by Tokyo Electron, Ltd.) andprebaked on a hot plate at 130° C. for 90 seconds to form a coating witha thickness of 300 nm. The above upper layer-forming composition wasapplied on the resulting coating by spin coating and prebaked (PB) at90° C. for 60 seconds to obtain a coating with a thickness of 90 nm.Ultra-pure water was injected onto the coating for 60 seconds from arinse nozzle of “CLEAN TRACK ACT8”, followed by spin-drying at 4,000 rpmfor 15 minutes and paddle development using the LD nozzle of the “CLEANTRACK ACT8” for 60 seconds to remove the upper layer. A 2.38% TMAHaqueous solution was used as a developer in the development step.Although the coating for use in immersion lithography was removed by thedevelopment step, the resist coating film which was not exposed toradiation remained as is. The thickness was measured using “Lambda AceVM-90” (manufactured by Dainippon Screen Mfg. Co., Ltd.) before andafter the experiment. If the change of the resist thickness was within0.5%, the resist coating was judged to exhibit no intermixing with theupper layer film for use in immersion lithography and the intermixingproperties were indicated as “Good”, and if the change of the resistthickness was more than 0.5%, the intermixing properties were indicatedas “Bad.”

(4) Stability Evaluation of Upper Layer-Forming Composition for Use inImmersion Lithography in Water (Water Resistance)

A coating (thicknesses: 30 nm) of the upper layer-forming compositionwas formed by spin-coating and baking (PB) at 90° C. for 60 seconds onan eight-inch silicon wafer using “CLEAN TRACK ACT8” (manufactured byTokyo Electron, Ltd.). The thickness was measured by using “Lambda AceVM-90”. Ultra-pure water was injected onto the wafer for 60 seconds fromthe rinse nozzles of “CLEAN TRACK ACT8”, followed by spin-drying at4,000 rpm for 15 seconds. The thickness of this substrate was measuredagain. When the amount of decrease in the thickness was 3% or less ofthe initial thickness, the stability was judged to be acceptable andindicated as “Good”, and if more than 3%, indicated as “Bad”.

(5) Evaluation of Patterning 1

The evaluation method of patterning of a resist using the above upperlayer film is described below.

After forming a coating with a thickness of 77 nm (after PB at 205° C.for 60 seconds) using an underlayer reflection preventing film “ARC29A”(manufactured by Brewer Science, Inc.) on an eight-inch silicon wafer byspin coating using “CLEAN TRACK ACT8” (manufactured by Tokyo Electron,Ltd.), patterning was carried out using the radiation-sensitive resincomposition containing the above-mentioned radiation-sensitive resin(A′) as the resin component. A film with a thickness of 205 nm wasprepared by spin coating and PB (130° C., 90 seconds), followed byforming the upper layer film by spin coating and PB (90° C., 60 seconds)to obtain a coating with a thickness of 90 nm. Next, after exposureunder the conditions of NA of 0.78, sigma of 0.85, and ⅔ Ann using anArF projection aligner “5306C” (manufactured by Nikon Corp.), ultra-purewater was injected onto the wafer from rinse nozzles of “CLEAN TRACKACT8” for 60 seconds, followed by spin-drying at 4,000 rpm for 15seconds. The resulting coating was baked (PEB) at 130° C. for 90 secondson a “CLEAN TRACK ACT8” hot plate, developed by paddle development usingthe LD nozzle of the “CLEAN TRACK ACT8”for 60 seconds, and rinsed withultra-pure water, followed by spin-drying at 4,000 rpm for 15 seconds.

90 nm line-and-space (1L1S) patterns were observed using a scanningelectron microscope (“S-9380” manufactured by Hitachi High-Tech FieldingCorporation) to determine an exposure dose at which a 1:1 line width was90 nm (optimum exposure dose). The minimum line-and-space dimensionresolved by the optimum exposure dose was taken as the resolution. Theresults are shown in Table 4. The cross-sectional configuration of 90 nmline-and-space patterns were observed using a scanning electronmicroscope (“S-4200” manufactured by Hitachi High-Tech FieldingCorporation). FIG. 1 shows the cross-sectional configuration of theline-and-space pattern. A line width Lb in the middle of a pattern 2 ona coating formed on a substrate 1 and a line width La on the upper partof the coating were measured. The configurations were judged as“rectangular” when 0.9<=(La−Lb)/Lb<=1.1 was satisfied; as “tapered” when(La−Lb)/Lb<0.9 was satisfied; and as “head-projected” when(La−Lb)/Lb>1.1 was satisfied.

In the case of Comparative Example 11, the patterning was evaluated byspin coating the radiation-sensitive resin composition and PB (130° C.,90 seconds) after forming a film with a thickness of 205 nm withoutforming an upper layer film.

(6) Evaluation of Patterning 2

The evaluation method of patterning of a resist using the above upperlayer film is described below.

After forming a coating with a thickness of 77 nm (after PB at 205° C.for 60 seconds) using an underlayer reflection preventing film “ARC29A”(manufactured by Brewer Science, Inc.) on an eight-inch silicon wafer byspin coating using “CLEAN TRACK ACT8” (manufactured by Tokyo Electron,Ltd.), patterning was carried out using “ArF AR1682J” (manufactured byJSR Corp.). The “AR1682J” film with a thickness of 205 nm was preparedby spin coating and PB (110° C., 90 seconds), followed by forming theupper layer film by spin coating and PB (90° C., 60 seconds) to obtain acoating with a thickness of 90 nm. Next, after exposure under theconditions of NA of 0.78, sigma of 0.85, and ⅔ Ann using an ArFprojection aligner “S306C” (manufactured by Nikon Corp.), ultra-purewater was injected onto the wafer from rinse nozzles of “CLEAN TRACKACT8” for 60 seconds, followed by spin-drying at 4000 rpm for 15seconds. The resulting coating was baked (PEB) at 110° C. for 90 secondson a “CLEAN TRACK ACT8” hot plate, developed by paddle development usingthe LD nozzle of the “CLEAN TRACK ACT8” for 60 seconds, and rinsed withultra-pure water, followed by spin-drying at 4000 rpm for 15 seconds.

90 nm line-and-space (1L1S) patterns were observed using a scanningelectron microscope (“S-9380” manufactured by Hitachi High-Tech FieldingCorporation) to determine an exposure dose at which a 1:1 line width was90 nm (optimum exposure dose). The minimum line-and-space dimensionresolved by the optimum exposure dose was taken as the resolution. Theresults are shown in Table 4. In addition, the cross-sectionalconfiguration of a 90 nm line-and-space pattern was observed as shown inFIG. 1 to measure the line width Lb in the middle of the film and theline width La on the upper part of the film. The configuration wasjudged as “rectangular” when 0.9<=(La−Lb)/Lb<=1.1 was satisfied; as“tapered” when (La−Lb)/Lb<0.9 was satisfied; and as “head-projected”when (La−Lb)/Lb>1.1 was satisfied.

In the case of Comparative Example 11, the patterning was evaluatedwithout forming an upper layer film after forming a film with athickness of 205 nm by spin coating the “AR1682J”, followed by PB (110°C., 90 seconds).

(7) Minimum Amount of Application

In Examples 1 to 30 and Examples 37 to 48, 4 g of the solid component ofthe resin shown in Table 1 and 96 g of a solvent or a mixture ofsolvents at a ratio shown in Table 4 or Table 5 were mixed and stirredfor two hours. The mixture was filtered through a filter with a poresize of 200 nm to obtain a solution, which was coated on an eight-inchsilicon wafer using “CLEAN TRACK ACT8” (manufactured by Tokyo Electron,Ltd.) and baked (PB) at 90° C. for 60 seconds. The amount of applicationwas changed at a 0.25 ml interval to determine the minimum amount foruniformly coating 95% of the surface of the eight-inch silicon waferwith the upper layer-forming composition.

In Examples 31 to 36, the upper layer film forming-compositions shown inTable 3 were coated on an eight-inch silicon wafer using “CLEAN TRACKACT8” (manufactured by Tokyo Electron, Ltd.) and baked (PB) at 90° C.for 60 seconds. The amount of application was changed at a 0.25 mlinterval to determine the minimum amount for uniformly coating 95% ofthe surface of the eight-inch silicon wafer with the upper layer-formingcomposition.

(8) Capability of Suppressing Elusion from Resist to Ultra-Pure Water(Elusion of Anion Part)

A 30×30 cm square silicon rubber sheet (manufactured by Kureha ElastomerCo., Ltd.) of which the center was hollowed in a circle with a diameterof 11.3 cm was placed on the center of an eight-inch silicon wafer whichwas previously treated with HMDS (100° C. for 60 seconds) using “CLEANTRACK ACT8” (manufactured by Tokyo Electron, Ltd.). The circularhollowed area of the center of the silicone rubber sheet was filled with10 ml of ultra-pure water using a 10 ml one-mark pipette.

After forming a coating with a thickness of 77 nm (after PB at 205° C.for 60 seconds) using an underlayer reflection preventing film “ARC29A”(manufactured by Brewer Science, Inc.) on an eight-inch silicon wafer byspin coating using “CLEAN TRACK ACT8” (manufactured by Tokyo Electron,Ltd.), the radiation-sensitive resin composition containing theabove-mentioned radiation-sensitive resin (A′) as the resin componentwas spin-coated and baked (PB) at 115° C. for 60 seconds to obtain afilm with a thickness of 205 nm. After the PB, a coating with athickness of 90 nm prepared by spin coating the upper layer-formingcomposition and baking (PB) at 90° C. for 60 seconds was placed on thesilicone rubber sheet so as to cause the coating to come in contact withthe ultra-pure water. This state was maintained for 10 seconds measuredby a stopwatch, whereupon the silicon wafer was removed. Aftercompletion of the experiment, the ultra-pure water was collected using aglass syringe for use as the analytical sample. The recovery rate of theultra-pure water after completion of the experiment was 95% or more.

The peak intensity of the anion part of the photoacid generator in theultra-pure water obtained by the above experiment was measured by liquidchromatography mass spectrometry (LC-MS) (LC section: “SERIES 1100”manufactured by AGILENT, MS section: “Mariner” manufactured byPerseptive Biosystems, Inc.) using a column (“CAPCELL PAK MG”manufactured by Shiseido Co., Ltd.) at a flow rate of 0.2 ml/min, andusing a solution of 0.1 wt % formic acid in a 3:7 mixture of water andmethanol as an eluant at 35° C. In this instance, peak intensities ofthe aqueous solutions of the photoacid generator used for theradiation-sensitive resin composition, in which the radiation-sensitiveresin (A′) is used as a resin component, at concentrations of 1 ppb, 10ppb, and 100 ppb were measured under the above conditions to prepare acalibration curve. The eluted amount was calculated from the above peakintensity using this calibration curve.

(9) Solvent Viscosity Measurement

The viscosity was measured according to JIS K2283 using a Canon-Fenskeviscometer.

TABLE 4 Solvent Resin Type Viscosity** Solubility RemovabilityIntermixing Delamination Example 1 A-1 DBE = 100 0.7 Good Good Good Good2 A-1 4M2P/DBE = 30/70 1.5 Good Good Good Good 3 A-1 4M2P/DBE = 70/302.2 Good Good Good Good 4 A-2 DBE = 100 0.7 Good Good Good Good 5 A-24M2P/DBE = 30/70 1.5 Good Good Good Good 6 A-2 4M2P/DBE = 70/30 2.2 GoodGood Good Good 7 A-3 DBE = 100 0.7 Good Good Good Good 8 A-3 4M2P/DBE =30/70 1.5 Good Good Good Good 9 A-3 4M2P/DBE = 70/30 2.2 Good Good GoodGood 10 A-4 DBE = 100 0.7 Good Good Good Good 11 A-4 4M2P/DBE = 30/701.5 Good Good Good Good 12 A-4 4M2P/DBE = 70/30 2.2 Good Good Good Good13 A-5 DBE = 100 0.7 Good Good Good Good 14 A-5 4M2P/DBE = 30/70 1.5Good Good Good Good 15 A-5 4M2P/DBE = 70/30 2.2 Good Good Good Good 16A-6 DBE = 100 0.7 Good Good Good Good 17 A-6 4M2P/DBE = 30/70 1.5 GoodGood Good Good 18 A-6 4M2P/DBE = 70/30 2.2 Good Good Good Good 19 A-7DBE = 100 0.7 Good Good Good Good 20 A-7 4M2P/DBE = 30/70 1.5 Good GoodGood Good 21 A-7 4M2P/DBE = 70/30 2.2 Good Good Good Good 22 A-8 DBE =100 0.7 Good Good Good Good 23 A-8 4M2P/DBE = 30/70 1.5 Good Good GoodGood 24 A-8 4M2P/DBE = 70/30 2.2 Good Good Good Good 25 A-9 DBE = 1000.7 Good Good Good Good 26 A-9 4M2P/DBE = 30/70 1.5 Good Good Good Good27 A-9 4M2P/DBE = 70/30 2.2 Good Good Good Good 28 A-10 DBE = 100 0.7Good Good Good Good 29 A-10 4M2P/DBE = 30/70 1.5 Good Good Good Good 30A-10 4M2P/DBE = 70/30 2.2 Good Good Good Good 31 Composition shown 0.7Good Good Good Good 32 in Table 3 1.5 Good Good Good Good 33 0.7 GoodGood Good Good 34 1.5 Good Good Good Good 35 0.7 Good Good Good Good 361.5 Good Good Good Good 37 A-5 4M2P/DIAE = 60/40 2.2 Good Good Good Good38 * 4M2P/DIAE = 60/40 2.2 Good Good Good Good Comparative 1 A-1 4M2P =100 5.2 Good Good Good Good Example 2 A-2 4M2P = 100 5.2 Good Good GoodGood 3 A-3 4M2P = 100 5.2 Good Good Good Good 4 A-4 4M2P = 100 5.2 GoodGood Good Good 5 A-5 4M2P = 100 5.2 Good Good Good Good 6 A-6 4M2P = 1005.2 Good Good Good Good 7 A-7 4M2P = 100 5.2 Good Good Good Good 8 A-84M2P = 100 5.2 Good Good Good Good 9 A-9 4M2P = 100 5.2 Good Good GoodGood 10 A-9 4M2P = 100 5.2 Good Good Good Good 11 — — — — — — —Patterning Patterning Coating Elusion Solvent evaluation 1 evaluation 2amount of anion Resin Type Resolution Shape Resolution Shape (ml) (ppb)Example 1 A-1 DBE = 100 85 nm Rect 80 nm Rect 0.50 0.3 2 A-1 4M2P/DBE =30/70 85 nm Rect 80 nm Rect 0.75 0.8 3 A-1 4M2P/DBE = 70/30 85 nm Rect80 nm Rect 1.25 1.7 4 A-2 DBE = 100 85 nm Rect 80 nm Rect 0.50 1.3 5 A-24M2P/DBE = 30/70 85 nm Rect 80 nm Rect 0.75 4.4 6 A-2 4M2P/DBE = 70/3085 nm Rect 80 nm Rect 1.25 6.3 7 A-3 DBE = 100 85 nm Rect 80 nm Rect0.50 0.2 8 A-3 4M2P/DBE = 30/70 85 nm Rect 80 nm Rect 0.75 0.6 9 A-34M2P/DBE = 70/30 85 nm Rect 80 nm Rect 1.25 1.2 10 A-4 DBE = 100 85 nmRect 80 nm Rect 0.50 0.2 11 A-4 4M2P/DBE = 30/70 85 nm Rect 80 nm Rect0.75 0.7 12 A-4 4M2P/DBE = 70/30 85 nm Rect 80 nm Rect 1.25 1.3 13 A-5DBE = 100 85 nm Rect 80 nm Rect 0.50 0.3 14 A-5 4M2P/DBE = 30/70 85 nmRect 80 nm Rect 0.75 0.8 15 A-5 4M2P/DBE = 70/30 85 nm Rect 80 nm Rect1.25 1.6 16 A-6 DBE = 100 85 nm Rect 80 nm Rect 0.50 0.2 17 A-6 4M2P/DBE= 30/70 85 nm Rect 80 nm Rect 0.75 0.6 18 A-6 4M2P/DBE = 70/30 85 nmRect 80 nm Rect 1.25 1.4 19 A-7 DBE = 100 85 nm Rect 80 nm Rect 0.50 0.220 A-7 4M2P/DBE = 30/70 85 nm Rect 80 nm Rect 0.75 0.8 21 A-7 4M2P/DBE =70/30 85 nm Rect 80 nm Rect 1.25 1.6 22 A-8 DBE = 100 85 nm Rect 80 nmRect 0.50 0.3 23 A-8 4M2P/DBE = 30/70 85 nm Rect 80 nm Rect 0.75 0.8 24A-8 4M2P/DBE = 70/30 85 nm Rect 80 nm Rect 1.25 1.7 25 A-9 DBE = 100 85nm Rect 80 nm Rect 0.50 0.3 26 A-9 4M2P/DBE = 30/70 85 nm Rect 80 nmRect 0.75 1.0 27 A-9 4M2P/DBE = 70/30 85 nm Rect 80 nm Rect 1.25 2.1 28A-10 DBE = 100 85 nm Rect 80 nm Rect 0.50 0.3 29 A-10 4M2P/DBE = 30/7085 nm Rect 80 nm Rect 0.75 0.8 30 A-10 4M2P/DBE = 70/30 85 nm Rect 80 nmRect 1.25 1.5 31 Compostion shown 85 nm Rect 80 nm Rect 0.50 0.4 32 inTable 3 85 nm Rect 80 nm Rect 0.75 0.8 33 85 nm Rect 80 nm Rect 0.50 0.534 85 nm Rect 80 nm Rect 0.75 1.0 35 85 nm Rect 80 nm Rect 0.50 0.5 3685 nm Rect 80 nm Rect 0.75 1.0 37 A-5 4M2P/DIAE = 60/40 85 nm Rect 85 nmRect 1.00 1.2 38 * 4M2P/DIAE = 60/40 85 nm Rect 85 nm Rect 1.00 1.3Comparative 1 A-1 4M2P = 100 85 nm Rect 80 nm Rect 1.75 1.8 Example 2A-2 4M2P = 100 85 nm Rect 80 nm Rect 1.75 7.7 3 A-3 4M2P = 100 85 nmRect 80 nm Rect 1.75 1.4 4 A-4 4M2P = 100 85 nm Rect 80 nm Rect 1.75 1.55 A-5 4M2P = 100 85 nm Rect 80 nm Rect 1.75 1.6 6 A-6 4M2P = 100 85 nmRect 80 nm Rect 1.75 1.6 7 A-7 4M2P = 100 85 nm Rect 80 nm Rect 1.75 1.78 A-8 4M2P = 100 85 nm Rect 80 nm Rect 1.75 1.9 9 A-9 4M2P = 100 85 nmRect 80 nm Rect 1.75 2.2 10 A-9 4M2P = 100 85 nm Rect 80 nm Rect 1.751.7 11 — — 85 nm Rect 80 nm Rect — — *A-1/A-5 = 70/30 **Unit ofviscosity: ×10⁻³ Pa · s

TABLE 5 Solvent Resin Type Viscosity** Solubility RemovabilityIntermixing Delamination Example 39 A-1 4M2P/Decane = 70/30 2.2 GoodGood Good Good 40 A-2 4M2P/Decane = 70/30 2.2 Good Good Good Good 41 A-34M2P/Decane = 70/30 2.2 Good Good Good Good 42 A-4 4M2P/Decane = 70/302.2 Good Good Good Good 43 A-5 4M2P/Decane = 70/30 2.2 Good Good GoodGood 44 A-6 4M2P/Decane = 70/30 2.2 Good Good Good Good 45 A-74M2P/Decane = 70/30 2.2 Good Good Good Good 46 A-8 4M2P/Decane = 70/302.2 Good Good Good Good 47 A-9 4M2P/Decane = 70/30 2.2 Good Good GoodGood 48 A-10 4M2P/Decane = 70/30 2.2 Good Good Good Good PatterningPatterning Coating Elusion Solvent evaluation 1 evaluation 2 amount ofanion Resin Type Resolution Shape Resolution Shape (ml) (ppb) Example 39A-1 4M2P/Decane = 70/30 85 nm Rect 80 nm Rect 1.00 1.8 40 A-24M2P/Decane = 70/30 85 nm Rect 80 nm Rect 1.00 6.2 41 A-3 4M2P/Decane =70/30 85 nm Rect 80 nm Rect 1.00 1.2 42 A-4 4M2P/Decane = 70/30 85 nmRect 80 nm Rect 1.00 1.1 43 A-5 4M2P/Decane = 70/30 85 nm Rect 80 nmRect 1.00 1.5 44 A-6 4M2P/Decane = 70/30 85 nm Rect 80 nm Rect 1.00 1.645 A-7 4M2P/Decane = 70/30 85 nm Rect 80 nm Rect 1.00 1.6 46 A-84M2P/Decane = 70/30 85 nm Rect 80 nm Rect 1.00 1.7 47 A-9 4M2P/Decane =70/30 85 nm Rect 80 nm Rect 1.00 2.0 48 A-10 4M2P/Decane = 70/30 85 nmRect 80 nm Rect 1.00 1.5 **Unit of viscosity: ×10⁻³ Pa · s

As shown in Tables 4 and 5, upper layer-forming compositions which canform a film stable in water during exposure to radiation in liquidimmersion lithography and is easily dissolved in an alkaline developerwere obtained in Examples 1 to 48. By using them, the amount ofapplication and the amount of elusion can be reduced, while maintainingresolution and developability equivalent to a common method. The upperlayer-forming composition of the embodiment of the present invention isthus very advantageous in the production of semiconductor devices.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

1. An upper layer-forming composition comprising: a resin dissolvable in a developer for a photoresist film which is to be covered by the upper layer-forming composition to form a pattern by exposure to radiation; and a solvent to dissolve the resin in the solvent, the solvent including a compound shown by a formula (1), R¹—O—R²  (1) wherein each of R¹ and R² independently represents a hydrocarbon group having 1 to 8 carbon atoms or a halogenated hydrocarbon group.
 2. The upper layer-forming composition according to claim 1, wherein the solvent does not cause intermixing of the photoresist film and the upper layer-forming composition.
 3. The upper layer-forming composition according to claim 1, wherein the solvent further includes a monohydric alcohol having 1 to 10 carbon atoms.
 4. The upper layer-forming composition according to claim 2, wherein the solvent further includes a monohydric alcohol having 1 to 10 carbon atoms.
 5. The upper layer-forming composition according to claim 1, wherein the resin includes a first recurring unit having a group shown by a formula (2), a second recurring unit having a group shown by a formula (3), a third recurring unit having a group shown by a formula (4), a fourth recurring unit having a carboxyl group, a fifth recurring unit having a sulfo group, or a combination thereof and has a weight average molecular weight measured by gel permeation chromatography of 2,000 to 100,000,

wherein each of R³ and R⁴ independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a fluoroalkyl group having 1 to 4 carbon atoms, R⁵ represents a fluoroalkyl group having 1 to 20 carbon atoms, and R⁶ represents an organic group having a polar group.
 6. The upper layer-forming composition according to claim 1, further comprising: an acid, an acid-generator which generates an acid by being exposed to radiation, or a combination of the acid and the acid-generator.
 7. A photoresist patterning method comprising: applying a photoresist composition to a substrate to form a photoresist film; applying the upper layer-forming composition according to claim 1 on the photoresist film to form an upper layer film; irradiating the photoresist film and the upper layer film with radiation using a liquid as a medium through a mask having a specific pattern to form a resist pattern; and developing the resist pattern.
 8. A photoresist patterning method comprising: applying a photoresist composition to a substrate to form a photoresist film; applying the upper layer-forming composition according to claim 2 on the photoresist film to form an upper layer film; irradiating the photoresist film and the upper layer film with radiation using a liquid as a medium through a mask having a specific pattern to form a resist pattern; and developing the resist pattern.
 9. A photoresist patterning method comprising: applying a photoresist composition to a substrate to form a photoresist film; applying the upper layer-forming composition according to claim 3 on the photoresist film to form an upper layer film; irradiating the photoresist film and the upper layer film with radiation using a liquid as a medium through a mask having a specific pattern to form a resist pattern; and developing the resist pattern.
 10. A photoresist patterning method comprising: applying a photoresist composition to a substrate to form a photoresist film; applying the upper layer-forming composition according to claim 4 on the photoresist film to form an upper layer film; irradiating the photoresist film and the upper layer film with radiation using a liquid as a medium through a mask having a specific pattern to form a resist pattern; and developing the resist pattern.
 11. A photoresist patterning method comprising: applying a photoresist composition to a substrate to form a photoresist film; applying the upper layer-forming composition according to claim 5 on the photoresist film to form an upper layer film; irradiating the photoresist film and the upper layer film with radiation using a liquid as a medium through a mask having a specific pattern to form a resist pattern; and developing the resist pattern.
 12. A photoresist patterning method comprising: applying a photoresist composition to a substrate to form a photoresist film; applying the upper layer-forming composition according to claim 6 on the photoresist film to form an upper layer film; irradiating the photoresist film and the upper layer film with radiation using a liquid as a medium through a mask having a specific pattern to form a resist pattern; and developing the resist pattern. 